Magnetic properties of Sr3-xCaxRu2O7

We report the magnetization data of single crystalline Sr3-xCaxRu2O7 (x = 1.5, 2.0, 3.0) grown by a floating-zone method. In the magnetic phase diagram of this system, a phase with a ferromagnetic correlation (0.5 ≤x ≤ 1.2) adjoins a two-dimensional (2D) metallic and antiferromagnetic phase (1.2 ≤ x ≤ 3). In the antiferromagnetic and 2D-metallic phase, the magnetic susceptibilities indicate that the magnetic easy axis changes continuously from the ab-plane to c-axis with increasing Sr content. Our results exhibit that the metamagnetic transition of Ca3Ru2O7, which is on the basis of a tunneling magnetoresistance, shifts to lower field and the transition becomes broad with increasing Sr content. Moreover, the magnetization data at T = 5 K for x = 1.5, 2.0 show a hysteresis, which suggests that the magnetic ground state is a canted antiferromagnetic one in this phase.