Magnetic coupling in transition-metal–doped LaSiFe_11.5 TM_0.5 (TM=Cr, Mn, Co and Ni)

CRANN and School of Physics, Trinity College Dublin - Dublin 2, Ireland and Department of Physics, Blackett Laboratory, Imperial College London - London SW7 2AZ, UK

Received: 1 April 2015
Accepted: 13 May 2015

Abstract

This study describes the effect of small concentration of transition metal (TM) dopants on the nature of magnetic and electronic structure of the metamagnetic La-Si-Fe. In agreement with experimental results, all of the investigated dopants are found to reduce the overall magnetisation of the parent compound, regardeless of the nature of actual spin arrangement. The large magnetic moment of Cr (−1.87μ_B) and Mn (−2.35μ_B) prefers to couple antiferromagnetically to the magnetic moments of Fe (2.22μ_B), whilst the Co and Ni spins are aligned ferromagnetically but with a lower magnetic moment of 1.40 and , respectively. The variation of electronic entropy due to the change in with the dopants suggests a reshaped metamagnetic energy landscape that can lead to an altered itinerant-electron metamagnetic (IEM) transition.