Defect induced ferromagnetism in Mn3Ga

S V Malik; E T Dias; P D Babu; K R Priolkar

doi:10.1088/1361-648X/ad14c9

Defect induced ferromagnetism in Mn₃Ga

J Phys Condens Matter. 2023 Dec 21;36(13). doi: 10.1088/1361-648X/ad14c9.

Authors

S V Malik¹, E T Dias¹, P D Babu², K R Priolkar¹

Affiliations

¹ School of Physical and Applied Sciences, Goa University, Goa 403206, India.
² UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC Campus, Mumbai 400 085, India.

PMID: 38086084
DOI: 10.1088/1361-648X/ad14c9

Abstract

Ni-substituted Mn₃Ga displays a weak ferromagnetism embedded in an antiferromagnetic (AF) phase. Upon field cooling, the alloy exhibits exchange bias and an open hysteresis loop, signifying kinetic arrest at room temperature. For the first time, a kinetic arrest is seen in a compound due to the first order transition of an embedded defect phase. A systematic study of crystal structure, local structure, and magnetic properties of Mn3-xNi_xGa (x= 0, 0.25) alloys reveal the origin of ferromagnetism in Mn_2.75Ni_0.25Ga is due to the segregation of a Heusler-type environment around Ni in the cubic Mn₃Ga matrix. Upon temper annealing at 400^∘C, these local structural defects around the Ni phase separate into a modulated ferromagnetic (FM) Ni-Mn-Ga Heusler phase. A strong interaction between the AF host and the FM defect phase gives rise to exchange bias. The first-order transition of the defect phase seems to be responsible for the observed kinetic arrest in Mn_2.75Ni_0.25Ga.

Keywords: Mn3Ga; antiferromagnets; mixed magnetic interactions.