Dynamical breakdown of the Ising spin-glass order under a magnetic field -: art. no. 180412

The dynamical magnetic properties of an Ising spin glass (SG) Fe0.55Mn0.45TiO3 are studied under various magnetic fields. Having determined the temperature and static-field-dependent relaxation time tau(T;H) from ac magnetization measurements under a do bias field by a general method, we first demonstrate that these data provide evidence for a SG phase transition only in zero field. We next argue that the data tau(T;H) of finite H can be well interpreted by the droplet theory, which predicts the absence of a SG phase transition in finite fields.