Electric transport and magnetism in the Heusler systems Pd2MnIn, Fe2MnSi and Fe2VSi under pressure

High pressure transport and magnetic measurements have been undertaken on the full Heusler alloys Pd2MnIn, Fe2MnSi and Fe2VSi.

In Pd2MnIn a change in the resistivity of the sample is observed, as gradually a peak appears under pressure. The phenomenon has been analyzed through a high temperature variable range hopping conduction. Alternatively, following some magnetic measurements that showed a difference between the ZFC and FC magnetization curves, the resistivity results were interpreted as a competition between the Kondo effect and the RKKY (Ruderman-Kittel-Kasuya-Yosida) interactions in the system, a phenomenon observed in some spin glass systems.

In Fe2MnSi, both the high pressure resistivity and the high pressure magnetic measurements point to a weak increase in the two magnetic transition temperatures. In addition, at low temperatures we observe a minimum in resistivity. The magnitude and the temperature of the minimum increases with pressure.

In Fe2VSi we provide some evidence, based on high pressure electric and thermoelectric transport measurements, of a possible pressure induced suppression of the structural transition that is present in the system at ambient pressure. The results are discussed in relation to an earlier theoretical study on the system.