Rotational-type spin reorientation in Nd<inf>1-x</inf>Dy<inf>x</inf>Co<inf>5</inf>and its application to thermomagnetic generator

Abstract

A rotational-type spin reorientation (SR) phenomenon is found in single crystals of Nd <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> Dy <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> , and the SR temperatures are controlled by Dy concentration near room temperature. In the SR temperature region an anomaly of a trapezoid shape is observed in specific heat, and it shows the second order nature of this phase transition. A thermomagnetic generator utilizing this phenomenon is invented, where thermal energy is converted directly into electric energy through the magnetic flux change accompanied with the SR. In an ideal case, the maximum energy that can be converted is evaluated as the magnetic anisotropy energy in the SR temperature region.