Magnetic and electrical properties of Gd7Rh3 single crystal

Magnetic and electrical properties of hexagonal Gd7Rh3 single crystals have been studied by measuring magnetization, magnetic susceptibility, and electrical resistivity. Gd7Rh3 shows antiferromagnetic order below TN=141 K as reported by Loebich et al; magnetic anisotropy is small in paramagnetic region. Metamagnetic transitions were observed at 4 K in the external magnetic field up to 130 kOe along the c-axis and in the c-plane. Electrical resistivity shows a characteristic hump just below TN due to the super-zone gap formation along the new Brillouin zone boundaries. High-temperature resistivity indicates that Gd7Rh3 has a semi-metallic band structure; the band gap energy 4.9 meV was obtained.