Magnetic, Electric and Thermal Properties of NdNiAl ₄ Single Crystal

The electrical resistivity, magnetization, specific heat and thermoelectric power measurements were performed on a NdNiAl4 single crystal along the principal axes of the orthorhombic cell. The easy axis of magnetization was parallel to the b axis below 20 K. The spin-flipping was observed at the magnetic field 4.4 T along the b axis at 2 K. The magnetic phase diagram was determined from the spin-flipping field. The huge magnetic anisotropy energy was estimated from the experiments of the magnetic susceptibility and magnetization. The energy gap newly occurred below T-N was observed in the electrical resistivity along the b axis. From this result we have speculated that a new magnetic periodicity is made along the b axis below TN. The magnetic susceptibility for the principal axes was discussed on the bases of the crystalline-electric-field and molecular-field theories.