Phase transformation in steel alloys for magnetocaloric applications; Fe$_{85-x}$Cr$_{15}$Ni$_{x}$ and Fe$_{85-x}$Cr$_{15}$Mn$_{x}$ as prototypes

TL;DR

This study uses first principles theory to demonstrate that alloying steel with Ni or Mn can induce a magnetic and structural phase transition, potentially enabling magnetocaloric effects suitable for room-temperature refrigeration.

Contribution

It predicts a novel magnetic and structural phase transition in common steel alloys through alloying, expanding their potential for magnetocaloric applications.

Findings

Transition from ferromagnetic bcc to paramagnetic fcc predicted.

High magnetic moment (~1.4μB/atom) at transition.

Potential for room-temperature magnetocaloric refrigeration.

Abstract

We here show by first principles theory that it is possible to achieve a structural and magnetic phase transition in common steel alloys like Fe$_{85}$Cr$_{15}$, by alloying with Ni or Mn. The predicted phase transition is from the ferromagnetic body centered cubic (bcc) phase to the paramagnetic face centered cubic (fcc) phase. The relatively high average magnetic moment of $\sim1.4\mu_{B}$/atom predicted at the transition suggests that stainless steel potentially can present a magnetocaloric effect strong enough to make these alloys good candidates for refrigeration applications operating at and around room temperature.