Magnetic phase diagram of UCoAl Original Research Article

Temperature T and pressure P dependences of the Landau coefficients for UCoAl are discussed by taking into account the magneto-volume effects and anisotropic spin fluctuations based on the Landau–Ginzburg theory. The P-dependence of the mean square amplitude of spin fluctuations is also discussed. A magnetic phase diagram is obtained with the parameters estimated from the observed magnetization curves under high pressures. The P-dependences of the characteristic temperatures T0 and Tmax, where the metamagnetic transition disappears and the susceptibility reaches a maximum, are estimated and compared with the observed results.