We report experimental observation of large anomalous Hall effect exhibited in non-collinear triangular antiferromagnet D019-type Mn3Ga with coplanar spin structure at temperatures higher than 100 K. The value of anomalous Hall resistivity increases with increasing temperature, which reaches 1.25 μΩ · cm at a low field of ~300 Oe at room temperature. The corresponding room-temperature anomalous Hall conductivity is about 17 (Ω · cm)−1. Most interestingly, as temperature falls below 100 K, a temperature-independent topological-like Hall effect was observed. The maximum peak value of topological Hall resistivity is about 0.255 μΩ · cm. The appearance of the topological Hall effect is attributed to the change of spin texture as a result of weak structural distortion from hexagonal to orthorhombic symmetry in Mn3Ga. Present study suggests that Mn3Ga shows promising possibility to be antiferromagnetic spintronics or topological Hall effect-based data storage devices.

In this study, we present the experimental observation that polycrystalline Mn2+xFe1−xGa (x = −0.2, 0, 0.2, 0.4) compounds can be synthesized to be D019-type (Ni3Sn-type) hexagonal structure with space group P63/mmc. A giant exchange bias field up to 1.32 kOe was achieved in hexagonal Mn2FeGa alloy at 5 K. A cluster glass state is confirmed by ac susceptibility measurement under different driving frequencies. Interestingly, robust horizontal and vertical shifts in magnetic hysteresis loop were simultaneously observed at 5 K under high cooling field up to 90 kOe. The large exchange bias is originated from the large exchange anisotropy between cluster glass phase and ferrimagnetic matrix. The vertical shift is thought to be attributed to the incomplete reversal of frozen cluster spins.

Spacer layer thickness dependence of exchange coupling in Co-enriched Co-Mn-Si/Cr/Co-Mn-Si epitaxial trilayers J. Appl. Phys. 110, 113901 (2011) Magnetometry and transport data complement polarized neutron reflectometry in magnetic depth profiling J. Appl. Phys. 110, 103914 (2011) (001) FePt graded media with PtMn underlayers Appl. Phys. Lett. 99, 212504 (2011) High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission Appl. Phys. Lett. 99, 194104 (2011) Current-induced domain wall motion in permalloy nanowires with a rectangular cross-section J. Appl. Phys. 110, 093913 (2011) Additional information on J. Appl. Phys. We investigated the spin-transfer switching in a full-Heusler Co 2 FeAl 0.5 Si 0.5 alloy spin-valve nanopillar through micromagnetic simulation. A two-step switching hysteresis loop due to the fourfold in-plane magnetocrystalline anisotropy of Co 2 FeAl 0.5 Si 0.5 layers was obtained. The simulation explains the experimental result of the resistance versus current hysteresis loop and yields good agreement with the measured critical current. Furthermore, the magnetization trajectory and magnetization distribution were shown and analyzed to elucidate the different characters of two-step switching.

Extensive first-principles calculations suggest that inverse Heusler compounds , , , and are the candidates to achieve fully compensated ferrimagnetic spin gapless semiconductors. It is shown that only the holes can be 100% spin polarized in , while both the excited electrons and the holes around the Fermi level 100% spin polarized in the others. A simple rule for searching potential fully compensated ferrimagnetic spin gapless semiconductors in Heusler compounds is proposed. Due to the spin gapless semiconducting and the fully compensated ferrimagnetic properties, these compounds offer distinct advantage towards the development of the practical spintronic devices.

A multilevel cell spin transfer switching process in a full-Heusler Co 2 FeAl 0.5 Si 0.5 alloy spin-valve nanopillar was investigated using micromagnetic simulations. An intermediate state of two-step spin transfer magnetization switching was reported due to the four-fold magnetocrystalline anisotropy; however, we discovered the intermediate state has two possible directions of À90 and þ90 , which could not be detected in the experiments due to the same resistance of the À90 state and the þ90 state. The domain structures were analyzed to determine the mechanism of domain wall motion and magnetization switching under a large current. Based on two intermediate states, we reported a multilevel bit spin transfer multi-step magnetization switching by changing the magnetic anisotropy in a full-Heusler alloy nanopillar. V

We investigated the spin-torque oscillator in a half-metallic Heusler alloy Co2MnSi (CMS) spin-valve nanopillar using micromagnetic simulations. Although it is known that the out-of-plane precession (OPP) usually has a larger power output than the in-plane precession (IPP), only IPP mode was experimentally observed in CMS. Our simulations revealed the fundamental and second harmonic radio frequency (rf) oscillations of the IPP mode, consistent with the experimental measurements in CMS-based pillars. Our simulations predicted that the OPP mode can be obtained under the condition of an initially antiparallel state, a small external magnetic field, and a sufficiently large current density

Effect of post-annealing on martensitic transformation and magnetocaloric effect in Ni45Co5Mn36.7In13.3 alloys J. Appl. Phys. 109, 07A939 (2011); 10.1063/1.3565189Magnetoresistance and magnetocaloric effect at a structural phase transition from a paramagnetic martensitic state to a paramagnetic austenitic state in

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