Structural and magnetic phase transitions of kagome-like compounds REBaCo 4O 7 (RE=Dy, Ho, Er, Tm, Yb, Lu)

Abstract

In a temperature range 5–300 K the specific heat C( T) on a new mixed valence cobalt oxides REBaCo 4O 7 (RE=Dy, Ho, Er, Tm, Yb, Lu) was investigated. The first-order structural phase transitions from hexagonal P6 3 mc to orthorhombic Cmc 2 1 phase was indicated by a peak-like anomaly in C( T) curves at T S∼160, 178, 224, and 280 K for RE=Lu, Yb, Tm, and Er correspondingly. The magnetic phase transitions was indicated as the changes of slope on the C( T) curves were found at corresponding temperatures: T N∼50, 74, 98, and 98 K for RE=Lu, Yb, Tm, and Er, correspondingly.