Magnetic nano- and microwires design, synthesis, properties and applications

Front Cover......Page 1
Magnetic Nano- and Microwires: Design, Synthesis, Properties and Applications......Page 4
Copyright......Page 5
Contents......Page 6
Contributors......Page 16
Preface......Page 26
Part One: Design, synthesis, and properties......Page 28
  1.1. Introduction......Page 30
   1.2.1. Magnetic nanowires with modulated diameter......Page 33
   1.2.2. Composition modulation: Multilayered nanowires......Page 36
   1.2.3. Relative orientation modulation: Radial nanowire array......Page 38
   1.3.1. Self-sustaining interconnected nanowire networks from ion-irradiated 3D polymeric templates......Page 40
   1.3.3. Self-sustaining interconnected nanowire network 3D structures from 3D AAO templates......Page 42
    1.3.3.1. Fabrication process and morphological description of the structures......Page 43
  References......Page 45
  2.1. Introduction......Page 48
  2.2. Atomic layer deposition technique......Page 49
  2.3. ALD on nanoporous templates: Tailored nanowire arrays......Page 54
  2.4. Magnetic nanotubes......Page 58
  2.5. Core-shell magnetic nanostructures......Page 62
  2.6. Diameter modulated nanowires......Page 64
   2.6.1. Magnetic properties of diameter modulated NiFe nanowire array......Page 68
   2.6.2. Micromagnetic simulations of single Ni and NiFe bisegmented diameter modulated nanowires......Page 70
   2.6.3. Magnetic properties of diameter modulated FeCo nanowires array......Page 73
  2.7. Conclusions......Page 78
  References......Page 79
  Further reading......Page 87
  3.1. Introduction......Page 88
  3.2. Nanoporous alumina template synthesis: Hard anodization......Page 90
   3.3.1. Metallic flux method......Page 93
   3.3.2. Metallic flux nanonucleation (MFNN) method......Page 96
   3.4.1. Fe3G4 nanowires: An itinerant metamagnetic compound......Page 97
   3.4.2. GdIn3: An intermetallic correlated electron system......Page 101
   3.4.3. Ga: A type I like superconductor at low dimension......Page 104
  References......Page 109
  4.1. Introduction......Page 112
  4.2. 3D-nanoprinted scaffolds for permalloy evaporation......Page 113
  4.3. Magnetic functionalization of scaffolds through permalloy evaporation......Page 117
  4.4. Dark-field magneto-optical Kerr effect (MOKE) magnetometry......Page 118
  4.5. Characterization of 3D magnetic domain-wall motion using dark-field MOKE magnetometry......Page 119
  4.6. Controlling switching mechanism and domain-wall injection in a suspended 3D nanowire......Page 124
  4.7. Summary and outlook......Page 127
  References......Page 128
  Further reading......Page 129
  5.1. Introduction......Page 130
  5.2. Synthesis......Page 131
   5.2.1. Axial heterostructures......Page 133
   5.2.2. Radial heterostructures......Page 136
   5.2.3. Nanowire arrays......Page 139
   5.2.4. Branched heterostructures......Page 140
  5.3. Potential applications......Page 142
    5.3.2.1. Unidirectional scattering......Page 144
    5.3.2.2. Structural colors......Page 146
    5.3.3.1. LEDs......Page 148
    5.3.3.2. Solar cells......Page 150
    5.3.3.3. Hybrid NW heterostructures......Page 151
   5.3.4. Spintronic applications......Page 152
  5.4. Future issues and outlook......Page 153
  5.5. Summary......Page 154
  References......Page 155
  6.1. Introduction......Page 162
   6.2.1. Polycarbonate membranes......Page 163
   6.2.2. Nanoporous alumina membranes......Page 165
   6.3.1. Electrochemical cell......Page 166
   6.3.2. Annular-shaped working electrodes......Page 167
   6.3.4. Tuning of the deposition time......Page 168
   6.3.6. Formation of hydrogen bubbles......Page 169
   6.3.8. Annular nanochannels......Page 170
   6.4.1. Atomic layer deposition......Page 172
   6.4.3. Sol-gel method......Page 174
   6.4.4. Wetting process......Page 175
   6.4.6. Thermal oxidation of nanowires (Kirkendall effect)......Page 176
   6.4.8. Hydrothermal process......Page 178
  6.5. Magnetism of cylindrical nanotubes......Page 180
   6.5.1. Magnetic interactions......Page 181
   6.5.2. Magnetization reversal......Page 183
   6.5.3. Magnetic domain wall dynamics......Page 185
   6.5.4. Exchange bias and thermal effects......Page 186
  6.6. Applications of magnetic nanotubes......Page 189
  6.7. Conclusions......Page 190
  References......Page 191
  7.1. Introduction......Page 212
    7.2.1.1. General principles......Page 213
    7.2.1.2. Morphology and structure......Page 214
    7.2.2.2. Structure and formation mechanism of cobalt nanorods and nanowires......Page 216
    7.2.2.3. Spontaneous formation of 3D arrays of Co nanorods in solution......Page 217
  7.3. Optimization of the magnetic properties of individual wires......Page 219
    7.3.1.1. Effect of the shape of elongated magnetic particles on the coercive field......Page 220
    7.3.1.2. Mean diameter and aspect ratio......Page 223
   7.3.2. Comparison with experimental results......Page 225
  7.4. 2D arrays of Co nanorods combining epitaxy and organometallic chemistry......Page 227
   7.4.2. Magnetic properties of 2D arrays of perpendicular nanorods......Page 228
    7.5.1.1. Influence of the degree of alignment......Page 231
    7.5.1.2. Effect of dipolar interactions......Page 233
    7.5.1.3. Influence of the packing density......Page 234
   7.5.2. Dense arrays of parallel nanorods......Page 235
   7.5.3. Consolidation of nanowires......Page 239
  7.6. Conclusion......Page 242
  References......Page 243
  Further reading......Page 246
  8.1. Introduction......Page 248
   8.2.1. Characterization methods......Page 251
   8.2.2. Main aspects of the magnetic behavior......Page 254
   8.2.3. Magnetostatic and magnetoelastic contributions......Page 257
  8.3. Domain wall propagation......Page 260
   8.3.1. Experimental techniques......Page 261
   8.3.2. Domain wall velocity and mobility......Page 262
   8.3.3. Shape of the propagating domain walls......Page 268
   8.3.4. Controlled motion of domain walls......Page 270
  8.4. Effects of structural transformations......Page 272
  8.5. Final remarks and future work......Page 274
  References......Page 277
  9.1. Introduction......Page 282
  9.2. Evaluation of applicability of glass-coated microwires for use in magnetocalorics......Page 284
  9.3. Preparation of glass-coated microwires......Page 286
  9.4. Experimental techniques used for characterization of Heusler-type microwires......Page 287
  9.5. Magnetic, magnetotransport, and structural properties microwires from Heusler alloys......Page 288
   9.5.1. Effect of annealing on magnetic properties of microwires from Heusler alloys......Page 291
   9.5.2. Magnetoresistance......Page 302
   9.5.3. Structure of Heusler-type microwires......Page 304
  9.6. Magnetocaloric effect of Heusler-type microwires......Page 309
  9.7. Magnetic hardening and exchange bias effect in Heusler-type microwires......Page 312
  Acknowledgments......Page 315
  References......Page 316
  Further reading......Page 321
Part Two: Magnetization mechanisms, domains and domain walls......Page 322
  10.1. Introduction......Page 324
   10.2.1. Equation of motion......Page 326
   10.2.2. Domain wall velocity......Page 327
   10.2.3. Depinning threshold current......Page 328
   10.2.4. Domain wall inertia......Page 329
   10.3.1. Sample preparation and experimental methods......Page 330
   10.3.2. Spin-orbit torque......Page 331
   10.3.3. Measurements of domain wall velocity......Page 333
   10.3.4. Determination of the magnetic chirality......Page 336
   10.3.5. Effective mass of chiral domain walls......Page 339
   10.3.6. Synchronous motion of highly packed coupled chiral domain walls......Page 343
  10.4. Conclusion......Page 347
  References......Page 348
  Further reading......Page 351
  11.1. Introduction......Page 352
    11.1.1.1. The thermal conductivity......Page 354
    11.1.1.2. Is the injected current pulse short enough?......Page 355
  11.2. Thermal behavior of a ferromagnetic nanostrip......Page 357
  11.3. Fabrication of the nanostrips: Some considerations......Page 363
   11.4.1. Micromagnetic model at zero or finite uniform temperature......Page 364
   11.4.2. Micromagnetic model and heat transport to account for the Joule effects......Page 366
    11.5.1.1. Field-driven DW motion......Page 370
    11.5.1.2. Current-driven DW motion......Page 373
   11.5.2. DW nucleation by a current pulse along a bit line......Page 375
    11.5.3.1. Deterministic analysis in the absence of the Joule heating effect......Page 377
    11.5.3.2. Current-assisted DW in the presence of Joule heating effect......Page 379
  11.6. Conclusions......Page 383
  References......Page 384
  Further reading......Page 387
   12.1.1. Perpendicular magnetic anisotropy......Page 388
   12.1.2. The Dzyaloshinskii-Moriya interaction......Page 389
   12.1.3. Magnetic domain walls......Page 390
   12.2.1. Physical mechanism and device geometries......Page 391
   12.2.2. E-field control of PMA......Page 394
   12.2.3. E-field control of magnetic DW motion......Page 395
   12.2.4. E-field control of DMI......Page 397
  12.3. He+ ion irradiation......Page 398
   12.3.1. Modification of PMA and DMI by ion irradiation......Page 399
   12.3.2. Magnetic domain wall motion and irradiation-induced disorder......Page 400
  12.4. Conclusion and outlook......Page 402
  References......Page 403
  13.1. Introduction......Page 408
  13.2. Skyrmion lines and monopoles in nanowires......Page 412
  13.3. Emergent electromagnetic fields......Page 418
  13.4. Other sample geometries and thermal fluctuations......Page 422
  13.5. Conclusions......Page 424
  References......Page 425
  14.1. Introduction......Page 430
  14.2. Hysteresis loops of magnetic nanowires......Page 431
  14.3. Magnetic domains and domain walls in straight magnetic nanowires......Page 435
  14.4. Domain wall velocity in cylindrical magnetic nanowires......Page 438
  14.5. Domains and domain walls in nanowires with geometrical modulations......Page 441
  14.6. Domain walls and domains in multisegmented Co/Ni nanowires......Page 446
  14.7. Conclusions......Page 448
  References......Page 449
   15.1.1. Fundamental and technological motivations for domain wall pinning......Page 454
   15.1.2. Types of pinning for nanowires......Page 455
   15.1.3. Existing theories and experiments......Page 456
   15.2.1. Domain walls in cylindrical nanowires......Page 457
   15.2.2. Geometry of modulation and potential barrier......Page 458
   15.2.3. Magnetic charges......Page 461
   15.2.4. Magnetic field generated by the modulation......Page 462
   15.2.5. Energy of interaction......Page 466
   15.3.1. Abrupt modulation......Page 467
   15.3.2. Smooth modulation......Page 469
   15.3.3. Protrusion: Double abrupt modulation......Page 471
  15.4. Modulation under applied current......Page 474
  References......Page 477
  16.1. Introduction to the imaging techniques......Page 482
  16.2. Synthesis and fabrication of modulated nanowires into the anodic aluminum oxide templates......Page 489
   16.2.2. Diameter-modulated nanowires obtained by pulsed anodization......Page 491
  16.3. Magnetic characterization of nanowire arrays......Page 494
  16.4. Magnetic characterization of individual nanowires with uniform diameter......Page 495
  16.5. Study of geometrically modulated nanowires......Page 500
  16.6. Multisegmented nanowires......Page 503
  16.7. Remarks and conclusion......Page 508
  References......Page 509
   17.1.1. Magnetic nanostructures......Page 518
   17.1.2. Ferromagnetic nanotubes......Page 519
   17.1.3. Measuring assemblies versus individual magnetic nanotubes......Page 520
  17.2. Magnetoresistance......Page 521
  17.3. Torque magnetometry......Page 524
  17.4. Magnetic imaging with X-rays......Page 528
  17.5. Scanning SQUID microscopy......Page 533
  17.6. Magnetic force microscopy......Page 536
  17.7. Conclusions and outlook......Page 538
  References......Page 539
  18.1. Introduction......Page 546
   18.2.2. Visualization of surface magnetic domain structures......Page 547
   18.2.3. Imaging of the magnetization reversal by MOKE microscopy......Page 551
  18.3. Elliptic domain structures......Page 552
  18.4. Spiral domain structures......Page 555
  References......Page 560
  Further reading......Page 561
  19.1. Introduction......Page 562
  19.2. Sixtus and Tonks measurements......Page 564
  19.3. Time-resolved measurement of the DW velocity......Page 567
  19.4. Braking and trapping a single-domain wall......Page 574
  19.5. Injection of domain walls......Page 580
  References......Page 582
  20.1. Introduction......Page 586
   20.2.1. Fixed frequency (cavity-based) FMR spectroscopy......Page 587
   20.2.2. Vector network analyzer-FMR spectroscopy......Page 588
   20.2.4. Time-resolved magneto-optical Kerr effect microscopy......Page 590
    20.3.1.1. Fabrication of ferromagnetic nanowire arrays in polymeric etched ion-track templates......Page 593
    20.3.1.2. Fabrication of ferromagnetic nanowire arrays in alumina templates......Page 594
   20.3.2. Static properties of ferromagnetic nanowire arrays......Page 595
   20.4.1. Dynamical behavior of saturated isolated ferromagnetic nanowires......Page 598
   20.4.2. Dynamical behavior of saturated ferromagnetic nanowire arrays......Page 600
   20.4.3. Dynamical behavior of unsaturated ferromagnetic nanowire arrays......Page 607
   20.4.4. Dynamical behavior of ferromagnetic nanowire arrays considering the magnetocrystalline anisotropy term......Page 612
   20.4.5. Dynamical behavior of multilayer ferromagnetic nanowire arrays......Page 616
   20.4.6. Dynamical behavior of gradient ferromagnetic nanowire arrays......Page 621
   20.5.1. Fabrication of 3-D ferromagnetic nanowire arrays......Page 622
   20.5.2. Static properties of 3-D ferromagnetic nanowire arrays......Page 625
   20.5.3. High-frequency behavior of 3-D ferromagnetic nanowire arrays......Page 626
  20.6. High-frequency applications and future perspectives of ferromagnetic nanowire arrays......Page 629
  References......Page 630
  21.1. Introduction......Page 640
    21.2.1.1. Static magnetic properties of nanowires......Page 642
    21.2.1.2. The role of shape anisotropy: Demagnetizing tensor of nonellipsoidal magnetic elements......Page 643
    21.2.1.3. Static dipolar interaction effects in nanowire arrays......Page 645
    21.2.1.4. Configurational phase transitions in arrays of nanowires......Page 646
  21.3. Magnetic nanowires in electromagnetic fields......Page 649
   21.3.1. SWs in magnetic nanowires......Page 652
    21.3.1.1. Dipolar-exchange spin-wave modes of individual cylindrical nanowires......Page 653
    21.3.1.2. Collective spin-wave modes in arrays of interacting nanowires......Page 659
    21.3.1.3. Spin waves in ferromagnetic nanowires with noncircular cross section......Page 661
    21.3.1.4. Magnetic structure and dynamics of multilayered nanowires and magnetic nanotubes......Page 663
    21.3.1.5. Effects of curvature and torsion on the magnetic dynamics in nanowires and nanotubes......Page 669
    21.4.1.1. EMW interactions with nanowire structures......Page 671
    21.4.1.2. Shape and size effects in the EMW propagation in nanoarrays......Page 676
    21.4.1.3. EMW scattering in nanowires at THz frequencies......Page 680
    21.4.2.1. Microwave devices based on magnetic nanowires......Page 684
    21.4.2.2. Magnetic nanowire metamaterials: Photonics and plasmonics......Page 687
  21.5. Conclusions and future trends......Page 689
  References......Page 690
Part Three: Sensing, thermoelectric, robotics, biomedical and microwave applications......Page 700
  22.1. Introduction......Page 702
  22.2. Fe-Ga alloy nanowires used in tactile sensors......Page 703
  22.3. Co/Cu multilayered nanowires for CPP-GMR structures......Page 707
  22.4. Nanowires used for biomedical applications......Page 710
  22.5. Long-range ordered porous AAO fabricated by double imprinting with line-patterned stamps......Page 716
  22.6. Conclusions......Page 717
  References......Page 720
  23.1. Introduction......Page 724
  23.2. Biocompatible magnetic nanowires......Page 725
  23.3. Magnetic nanowires for drug delivery......Page 728
  23.4. Magnetic nanowires for cancer treatment......Page 730
  23.5. Magnetic nanowires as MRI contrast agents......Page 732
  23.6. Magnetic nanowire cell scaffolds......Page 733
  23.7. Conclusion......Page 735
  References......Page 736
  24.1. Introduction......Page 742
  24.2. Short history......Page 743
  24.3. Thermopower......Page 744
   24.3.2. Thermopower sources in parallel......Page 747
  24.4. Temperature-dependent thermopower......Page 748
   24.4.1. Phonon-drag thermopower......Page 749
   24.4.2. Influence of nanostructuring......Page 750
  24.5. Origin of the magnetic field dependence......Page 752
   24.5.1. Magneto-thermopower......Page 754
  References......Page 757
  25.1. Introduction to magnetostrictive Fe-Ga alloys......Page 764
  25.2. Modeling and micromagnetics simulations of Fe-Ga nanowires......Page 771
  25.3. Fabrication of Fe-Ga nanowires......Page 776
  25.4. Structural and magnetic characterization of Fe-Ga and Fe-Ga/Cu nanowires......Page 778
  25.5. Actuation using Fe-Ga/Cu nanowires......Page 786
  25.6. Sensing using Fe-Ga/Cu nanowires......Page 794
  25.7. Closing remarks......Page 799
  References......Page 800
  26.1. Introduction......Page 804
  26.2. Fabrication techniques for nanowire-based swimmers......Page 807
  26.3. Magnetically driven nanowire-based swimmers......Page 809
   26.3.1. Corkscrew locomotion......Page 811
   26.3.2. Surface-walking locomotion......Page 813
   26.3.3. Undulatory (S-like) locomotion......Page 815
  26.4. Chemically propelled nanowire-based swimmers......Page 816
  References......Page 822
  27.1. Introduction......Page 828
  27.2. Template-assisted electrodeposition of 3D magnetic NW and NT networks......Page 829
   27.3.1. Magnetic and magneto-transport properties of interconnected homogenenous NW networks......Page 832
   27.3.2. Interconnected Ni NT networks with controlled structural and magnetic properties......Page 839
   27.4.1. Spin-dependent thermoelectric transport in multilayered NW networks......Page 843
   27.4.2. Magnetic control in heat management......Page 849
  27.5. Conclusion and future perspectives......Page 852
  References......Page 853
  28.1. Introduction......Page 860
   28.2.1. Production......Page 861
    28.2.2.1. Magnetic field sensing......Page 864
    28.2.2.2. Stress sensing using bistable microwires......Page 867
    28.2.2.3. Stress in 3-D printed materials......Page 868
    28.2.2.5. Sensing intracranial temperature......Page 870
    28.2.2.6. Monitoring intracranial temperature in titanium implants......Page 873
    28.2.2.7. Biocompatibility and technical compatibility of glass-coated microwires......Page 874
    28.2.2.8. Chemical sensors based on bistable microwires......Page 876
   28.2.3. Glass-coated Heusler-based SMART actuators......Page 877
    28.2.3.1. Magnetocaloric applications......Page 879
    28.2.3.2. Shape memory actuators: SMART actuators......Page 885
  28.3. Conclusions......Page 888
  Acknowledgments......Page 889
  References......Page 890
  29.2. Working principle......Page 896
   29.2.1. Second harmonic mode......Page 897
   29.2.2. Fundamental mode......Page 898
  29.3. Circumferential excitation field......Page 899
  29.4. Bimetallic wires......Page 902
  29.5. Noise and thermal treatment of the wire......Page 903
  29.6. Offset......Page 907
  29.7. Effect of wire geometry......Page 911
  29.8. Applications......Page 913
  References......Page 914
  Further reading......Page 915
  30.1. Introduction......Page 916
  30.2. Tunable magnetic configuration in amorphous wire......Page 917
   30.2.1. Tuning the anisotropy with applied stress and current annealing......Page 919
   30.2.2. Temperature effects......Page 921
  30.3. Dynamic permeability in microwires......Page 922
   30.3.1. Permeability spectra in wires with near-circumferential anisotropy......Page 923
   30.3.2. Permeability spectra in wires with the axial anisotropy near Tc......Page 924
  30.4. High-frequency impedance: Effects of external dc field, stress, and temperature......Page 925
   30.4.1. Magnetoimpedance plots vs. magnetic field......Page 926
   30.4.2. Magnetoimpedance vs. external stress......Page 927
   30.4.3. Impedance behavior near the Curie temperature......Page 929
   30.5.1. Electric polarization of a ferromagnetic wire......Page 931
   30.5.2. Tuning the current distribution and polarization......Page 933
   30.5.3. Application to wireless sensors......Page 935
  30.6. Microwire composites as artificial dielectrics with tunable permittivity and permeability......Page 936
   30.6.1. Effective permeability of wire composites......Page 937
   30.6.2. Effective permittivity of composites with finite-length wires (wire dipoles)......Page 938
   30.6.3. Effective permittivity of composites with continuous wires......Page 939
  References......Page 942
  31.1. Introduction......Page 946
  31.2. Microwave absorption theory......Page 947
   31.3.1. CNT-based polymer composites......Page 950
   31.3.3. Graphene-based polymer composites......Page 953
   31.3.4. Graphene-based magnetic composites and hybrids......Page 954
  31.4. Microwave absorption and metamaterial properties of amorphous wire composites......Page 955
  31.5. Tunable microwave absorption of polymer composites incorporating nano-carbon/amorphous wire hybrid fibers......Page 957
   31.5.1. Microwave absorption of polymer composites incorporating CNT/amorphous wire hybrid fibers......Page 963
   31.5.2. Microwave absorption of polymer composites incorporating rGO/amorphous wire hybrid fibers......Page 969
  31.6. Tunable negative permittivity of metacomposites incorporating nano-carbon/amorphous wire hybrid fibers......Page 973
   31.6.1. Tunable negative permittivity of metacomposites incorporating CNT/amorphous wire hybrid fibers......Page 974
   31.6.2. Tunable negative permittivity of metacomposites incorporating rGO/AW hybrid fibers......Page 978
   31.7.1. Summary......Page 982
  Acknowledgments......Page 983
  References......Page 984
Index......Page 992
Back Cover......Page 1012