K. Iwata

Structural Distortion and Physical Properties in Double-Layered Ruthenate Sr3-xCaxRu2O7

We have investigated the structural, magnetic, and electronic properties of single-crystalline Sr 3- x Ca x Ru 2 O 7 (0 ≤ x ≤3) grown by a floating-zone method. The results of X-ray diffraction, magnetic susceptibility, specific heat, and electrical resistivity measurements reveal that this system shows a novel phase diagram. With increasing Ca content, the enhanced paramagnetism of Sr 3 Ru 2 O 7 is suppressed, and a phase with a ferromagnetic correlation (\(0.5 \lesssim x \lesssim 1.2\)) emerges. This phase adjoins an antiferromagnetic two-dimensional metallic phase (\(1.2 \lesssim x \leq 3.0\)). At the border between these two phases, discontinuous changes in the lattice parameters are observed. In the ferromagnetically correlated phase, the density of states is significantly enhanced. In the antiferromagnetic phase, the magnetic easy axis changes continuously from the c -axis to the a b -plane with increasing Ca content. These magnetic and electronic properties are strongly coupled with structural dist...

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.