Extraordinarily strong magneto-responsiveness in phase-separated LaFe2Si

Abstract

<p>Materials responding vigorously to minor variations of external stimuli with negligible <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/hysteresis" title="Learn more about hysteresis from ScienceDirect's AI-generated Topic Pages">hysteresis</a> could revolutionize many of the energy technologies, including refrigeration, actuation, and sensing. We report a combined experimental and theoretical study of a two-phase composite, naturally formed at the LaFe2Si <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/stoichiometry" title="Learn more about stoichiometry from ScienceDirect's AI-generated Topic Pages">stoichiometry</a>, which exhibits a nearly anhysteretic, two-step first-order ferromagnetic-to-paramagnetic phase transformation with enhanced sensitivity to an external magnetic field. Other unusual properties include a large plateau-like positive <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/magnetoresistance" title="Learn more about magnetoresistance from ScienceDirect's AI-generated Topic Pages">magnetoresistance</a>, magnetic-field-induced temperature and entropy changes occurring over a wide temperature range, and a Griffiths-like phase associated with short-range ferromagnetic clustering in the paramagnetic state. The heat capacity, magnetization, <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/mossbauer-spectroscopy" title="Learn more about Mössbauer spectroscopy from ScienceDirect's AI-generated Topic Pages">Mössbauer spectroscopy</a>, and <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/electrical-resistivity" title="Learn more about electrical resistivity from ScienceDirect's AI-generated Topic Pages">electrical resistivity</a>, all exhibit characteristic, unusually sharp, first-order <a href="https://www.sciencedirect.com/topics/physics-and-astronomy/discontinuity" title="Learn more about discontinuities from ScienceDirect's AI-generated Topic Pages">discontinuities</a> even in magnetic fields as high as 100 kOe. We expect that similar phenomena could be designed in other mixed-phase systems, leading to novel functionalities, such as giant caloric effects in many yet undiscovered or/and underperforming <a href="https://www.sciencedirect.com/topics/materials-science/intermetallics" title="Learn more about intermetallic compounds from ScienceDirect's AI-generated Topic Pages">intermetallic compounds</a>.</p>