Magnetic Properties of Pure Galvinoxyl under Pressure. Suppression of the Structural Change and Observation of the Magnetic Ordering

抄録

We have developed a high-pressure clamp cell made of Cu-Ti alloy, which can be equipped to a Quantum Design MPMS SQUID magnetometer. The precise magnetic measurements is possible by using this clamp cell. We have discovered that the structural change of organic radical, galvinoxyl is suppressed by pressurization. Magnetic and thermal properties under pressure have been examined. This compound under 7 kbar is a quasione-dimensional Heisenberg ferromagnet with 2J/k_B≈20K. Interchain interaction is antiferromagnetic and a three-dimensional antiferromagnetic phase transition is observed at 0. 72 K.