Spin-Valve-Like Magnetoresistance in Mn2NiGa at Room Temperature

Singh, Sanjay ; Rawat, R. ; Muthu, S. Esakki ; D’Souza, S. W. ; Suard, E. ; Senyshyn, A. ; Banik, S. ; Rajput, P. ; Bhardwaj, S. ; Awasthi, A. M. ; Ranjan, Rajeev ; Arumugam, S. ; Schlagel, D. L. ; Lograsso, T. A. ; Chakrabarti, Aparna ; Barman, S. R. (2012) Spin-Valve-Like Magnetoresistance in Mn2NiGa at Room Temperature Physical Review Letters, 109 (24). ISSN 0031-9007

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Official URL: http://doi.org/10.1103/PhysRevLett.109.246601

Related URL: http://dx.doi.org/10.1103/PhysRevLett.109.246601

Abstract

Spin valves have revolutionized the field of magnetic recording and memory devices. Spin valves are generally realized in thin film heterostructures, where two ferromagnetic (FM) layers are separated by a nonmagnetic conducting layer. Here, we demonstrate spin-valve-like magnetoresistance at room temperature in a bulk ferrimagnetic material that exhibits a magnetic shape memory effect. The origin of this unexpected behavior in Mn2 NiGa has been investigated by neutron diffraction, magnetization, and ab initio theoretical calculations. The refinement of the neutron diffraction pattern shows the presence of antisite disorder where about 13% of the Ga sites are occupied by Mn atoms. On the basis of the magnetic structure obtained from neutron diffraction and theoretical calculations, we establish that these antisite defects cause the formation of FM nanoclusters with parallel alignment of Mn spin moments in a Mn2 NiGa bulk lattice that has antiparallel Mn spin moments. The direction of the Mn moments in the soft FM cluster reverses with the external magnetic field. This causes a rotation or tilt in the antiparallel Mn moments at the cluster-lattice interface resulting in the observed asymmetry in magnetoresistance.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:123014
Deposited On:02 Sep 2021 04:27
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