Magnetocaloric effect, magnetic domain structure and spin-reorientation transitions in HoCo5 single crystals

A study on the magnetocaloric effect (MCE) has been carried out on the HoCo5 single crystal using a direct method in the temperature range 78–300 K and in a magnetic field of 1.3 T at various orientations of the single crystal with respect to the direction of external magnetic field. Our research has shown that magnetic anisotropy strongly affects magnitude and sign of the MCE in the regions of spin-reorientation phase transitions. In addition, the magnetic domain structure of the HoCo5 single crystal in (0 0 1) plane in the temperature range from room temperature down to 4.2 K was investigated.

Research Highlights
► The magnetic domain structure at SRT and compensation temperature was observed.
► The MCE of HoCo5 single crystal depends essentially upon the orientation of the magnetic field.
► At the magnetization along the c-axis, the MCE has a negative sign, δTad =−0.2 K at 170 K.
► At the magnetization along the a-axis δTad = 0.12 K at 180 K.