Adiabatic Temperature Changes at Structural and Magnetic Phase Transitions in Ni45Mn43CoSn11 at High Magnetic Fields

Abstract

The adiabatic temperature change ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm {ad}}$ </tex-math></inline-formula> ) in Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">45</sub> Mn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">43</sub> CoSn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> has been measured by a direct method in magnetic field changes up to 14 T. Large reversible magnetocaloric effects resulting in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm {ad}}$ </tex-math></inline-formula> of about = −11 and 5 K have been observed for magnetic field changes of 14 T at the magnetostructural ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{A} \sim 260$ </tex-math></inline-formula> K) and magnetic transitions ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{C} \sim 320$ </tex-math></inline-formula> K), respectively. The impact of the thermomagnetic history on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm {ad}}$ </tex-math></inline-formula> at high magnetic fields has been reported. The significant observed changes in the relaxation time of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta T_{\mathrm {ad}}$ </tex-math></inline-formula> , depending on the type of the phase transitions, magnetization, and demagnetization cycle are discussed.