Spintronics is one of the emerging research fields in nanotechnology and has been growing very rapidly. Studies spintronics were started after discovery giant magnetoresistance 1988, which utilized spin-polarized electron transport across a non-magnetic metallic layer. Within 10 years, this had implemented into hard disk drives, most common storage media, followed by recognition through award Nobel Prize for Physics 19 years later. We have never experienced such fast development any...

We study the temperature and bias-voltage dependence of magnetoresistance (MR) in insulating Co-Al-O granular films. The MR exhibits strong is enhanced more than 20% at low temperatures, while it has no appreciable change dependence. results provide clear evidence for successive onset higher-order processes spin-dependent tunneling between large granules through intervening small ones with Coulomb blockade. remarkable contrast consistently explained.

The magnetization processes of highly ordered FePt(001) films with large perpendicular magnetic anisotropy have been studied. film morphology was controlled from isolated particles to continuous by varying the nominal thickness (tN) FePt sputter deposited directly on a MgO(001) substrate at an elevated temperature. A drastic change in coercivity one order magnitude has found critical (tN=45 nm) where changes particulate state. huge exceeding 40 kOe achieved tN=10 nm, which comprises single...

L 1 0 ordered FePt alloy films with large magnetic anisotropy have been successfully prepared by alternating Fe(001) and Pt(001) monatomic layers on MgO (001) substrates at low temperatures below 230 °C. In addition to the fundamental (002) peak, (003) superlattice peaks clearly observed in x-ray diffraction patterns for all samples, indicating formation of L10 structure. The magnetization measurements show that samples are perpendicularly magnetized. Large uniaxial (Ku=3.0×107 erg/cc) high...

A large tunnel magnetoresistance (TMR) ratio of 753% has been observed at 2 K in a magnetic junction (MTJ) using Co2MnSi Heusler alloy electrode and crystalline MgO barrier. This TMR is the largest reported to date MTJs electrode. Moreover, we have 217% room temperature (RT). RT much larger than that an amorphous Al-oxide However, dependence still because inelastic tunneling antiparallel configuration.

Microstructure and magnetization processes of highly ordered FePt(001) films with large perpendicular magnetic anisotropy have been studied. The film morphology was controlled from assemblies single-domain nanoparticles to those multidomain islands by varying the nominal thickness (tN) FePt sputter-deposited on a heated MgO(001) substrate. change in process rotation domain wall displacement is clearly demonstrated initial curves. Huge coercivities as high 70 105kOe achieved particles at room...

Fully epitaxial current-perpendicular-to-plane giant magnetoresistance (MR) devices with half-metallic ${\text{Co}}_{2}\text{MnSi}$ (CMS) electrodes and a Ag spacer were fabricated to investigate the relationship between chemical ordering in CMS its MR properties, including bulk interface spin-asymmetry coefficients $\ensuremath{\beta}$ $\ensuremath{\gamma}$. CMS/Ag/CMS annealed at $550\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ shows largest ratio: 36.4% 67.2% RT 110 K,...

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) characteristics were investigated in a Co2MnSi (CMS)/Ag/CMS fully epitaxial device and compared to those CMS/Cr/CMS systematically. Reflection high-energy electron diffraction transmission microscopy images showed the two samples had no remarkable differences little interdiffusion. The large spin-asymmetry of scattering was found at CMS/Ag inteface with that CMS/Cr interface. Finally, largest magneto-resistance (MR) ratio 28.8%...

Fully epitaxial Co2FexMn1−xSi(CFMS)/Ag/Co2FexMn1−xSi current-perpendicular-to-plane giant magnetoresistive devices with various Fe/Mn ratios x and top CFMS layer thicknesses tCFMS were prepared. The highest magnetoresistance (MR) ratios, 58% at room temperature 184% 30 K, observed in the sample = 0.4 3 nm. Enhancement of interface spin-asymmetry was suggested for compared that 0. A MR ratio also even a very thin trilayer structure, CFMS(4 nm)/Ag(3 nm)/CFMS(2 nm), which is promising...

The recently discovered spin Seebeck effect (SSE) which generates voltage due to a temperature gradient in ferromagnets, was systematically studied half-metallic Heusler compound ${\mathrm{Co}}_{2}\mathrm{MnSi}$ (CMS)/Pt thin films investigate the of polarization ferromagnetic layer on SSE. An epitaxial film CMS with an almost perfect $B$2-ordered structure prepared directly MgO(001) substrate. measurement performed at room for various differences, \ensuremath{\Delta}$T$ $=$ 0--20 K between...

We propose a new-type of thermopile consisting two ferromagnetic materials with anomalous Nernst effects (ANEs) opposite signs. L10-FePt and L10-MnGa have been chosen as the because they show large ANEs The combination perpendicularly magnetized FePt MnGa wires enhances ANE voltage effectively. in in-plane films induced by applying perpendicular temperature difference shows no variation against film thickness, which is promising characteristic for thermoelectric applications internal...

The anomalous Nernst effect (ANE) has been investigated in alternately-stacked multilayer films comprising paramagnetic and ferromagnetic metals. We found that the ANE is enhanced with increasing number of paramagnet/ferromagnet interfaces keeping total thickness constant, enhancement appears even absence magnetic proximity effects; similar behavior was observed not only Pt/Fe multilayers but also Au/Fe Cu/Fe free from ferromagnetism. This universal metallic suggests presence unconventional...

Tetrataenite (L10-FeNi) is a promising candidate for use as permanent magnet free of rare-earth elements because its favorable properties. In this study, single-phase L10-FeNi powder with high degree order was synthesized through new method, nitrogen insertion and topotactic extraction (NITE). the FeNiN, which has same ordered arrangement L10-FeNi, formed by nitriding A1-FeNi ammonia gas. Subsequently, FeNiN denitrided reaction to derive an parameter 0.71. The transformation disordered-phase...

Material dependence of the anomalous Nernst effect (ANE) in perpendicularly magnetized ordered-alloy thin films is systematically investigated. The ANE was found to have a tendency increase simply as uniaxial magnetic anisotropy increased at room temperature. increases temperature from 10 300 K for all materials. However, signs Fe-based ordered-alloys (L10-FePt and L10-FePd) Co/Ni multilayer are opposite those Mn-based (L10-MnGa D022-Mn2Ga). Ordered-alloys with larger anisotropies reveal...

We prepared L10-ordered FeNi alloy films by alternate deposition of Fe and Ni monatomic layers, investigated their magnetic anisotropy. employed a non-ferromagnetic Au–Cu–Ni buffer layer with flat surface good lattice matching to L10-FeNi. An L10-FeNi film grown on Au6Cu51Ni43 showed large uniaxial anisotropy energy (Ku = 7.0 × 106 erg cm−3). Ku monotonically increased the long-range order parameter (S) L10 phase. Fe–Ni composition dependence alternating 1 − x + layers (− 0.4 < 0.4)....

An FeAu ordered alloy has been fabricated artificially by depositing alternately monatomic layers of Fe and Au. Neither intermediate phase nor intermetallic compound is known for the Fe–Au system in equilibrium state. Nevertheless, x-ray diffraction prepared films shows definite superlattice lines corresponding to L10 structure, it metastable at room temperature. The obtained ferromagnetic, moment 2.5±0.3 μB, a considerably high Curie temperature over temperature, large uniaxial magnetic...

Current-induced magnetization reversal of perpendicularly magnetized layers was studied in current-perpendicular-to-plane giant magnetoresistance pillars with L10-FePt (001) layers. The FePt exhibited strong perpendicular magnetic anisotropy the order 107erg∕cm3. A series curves after applying pulse currents different current densities showed that current-induced from an antiparallel to a parallel alignment occurred at density 108A∕cm2 assistance field.

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of the multilayer thin film using a full-Heusler Co2MnSi (CMS) phase as ferromagnetic electrodes has been investigated. A Cr buffer (10nm)∕CMS (50nm)∕Cr spacer (3nm)∕CMS (10nm)∕Cr cap (3nm) was grown on MgO(100) substrate. The 50nm thick CMS layer which deposited at 573K epitaxially and had an L21 structure. resistance change-area product (ΔRA) room temperature 19mΩμm2, is one order magnitude larger than those in previously...

The anomalous Nernst effect in a perpendicularly magnetized L10-ordered epitaxial FePt(001) thin film has been investigated, and the coefficient angle of FePt were experimentally evaluated. Furthermore, voltage due to spin-Hall device was simulated by finite element method. A good agreement between experiment simulation found. It revealed that could be quantitatively discussed even nanoscale devices.

The coercivity (Hc) of a perpendicularly magnetized FePt layer was modulated by applying the voltage (Vapp) to Hall device through MgO and Al–O insulating layers. A change in ∼40 Oe Hc observed changing Vapp from −13 13 V. From quantitative analysis effect on Hc, anisotropy energy application evaluated be 18.6 fJ/V m, which same order as theoretical prediction. role for also discussed.