| Magnetic-field-induced irreversibility in specific heat of UNiAl (2002) | |||||||||
Abstract | |||||||||
| Results of low-temperature specific-heat ðCpÞ measurements of UNiAl single crystal in magnetic fields Bp14T are presented. At temperatures o7K, this antiferromagnet exhibits a first-order metamagnetic transition at the critical field BcE11:4 T (when applied parallel to the c-axis). In the same temperature range, different Cp vs. T curves are obtained in zero magnetic field depending on the magnetic history of the sample (zero-field-cooled (ZFC)=cooling to To7K in zero field, field cooled (FC)=cooling in a field of 14T parallel to c). The magnetic-field-induced irreversibility is clearly evidenced on the Cp=T vs. B data obtained at 3.2 K. For a measurement cycle; 0 (starting from ZFC state)-14-0T the ''increasing field'' Cp; ZFC=T and ''decreasing field'' Cp; FC=T data clearly differ in fields o9T and ðCp; ZFC=TÞ0 T > ðCp; FC=TÞ0 T: However in both cases, we have observed (for Bo9T) a Cp=TBkcB2 dependence with different kc values. The results are discussed in the context of earlier-reported magnetic-history effects in magnetic and other electronic properties. | |||||||||
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