Magnetic phase transitions in (Fe1−xTx)3Ga4 alloys

Abstract

The magnetic ordering in the series of transition metal alloys (Fe1−xTx)3Ga4 with T=Ni and Ti having values of x in the range 0.05⩽x⩽0.20 has been investigated at high fields and low temperatures. Magnetization measurements revealed that in contrast to other T substitutions, Ni and Ti induce completely different types of effects on the magnetic properties. In the case of Ni substitution a ferrimagnetic-like type of magnetic order is induced at low compositions and low temperatures and Ti produces a ferromagnetic ground state. For Ti alloys with low composition as the temperature is increased a field induced transition starts to appear at about 50 K which persists up to room temperature suggesting a phase transition from a ferromagnetic to an antiferromagnetic state. The phase diagrams of the Ni and Ti system are explainable in terms of the Moriya-Usami and Isoda theories. Preliminary neutron diffraction measurements on the Ni alloys carried out at ILL suggest the existence of short-range order over a certain temperature range. The behavior observed so far on the various substituted systems leads us to believe that there is a clear relation between the magnetic properties and the relative position of the substitution element with respect to Fe in the Periodic Table.

Altering the magnetic ordering of Fe$_{3}$Ga$_{4}$ via thermal annealing and hydrostatic pressure

“…It has been shown that doping can effectively tune the IDSW to FM transition temperature as well as the low temperature FM to ISDW transition. 16,[28][29][30][31] Similarly, previous work has shown that external pressure is effective at tun- ing the low temperature FM-ISDW transition temperature, but the effect on the high temperature ISDW-FM transition temperature has not been reported. 20,32 From these works, it appears that intermediate IDSW is sensitive to effects caused by doping through electron count changes and/or structural changes which in turn effect the electronic structure in this regime; although this has not be rigorously studied.…”