Double metamagnetic transition in the bilayer ruthenateSr3Ru2O7

Abstract
We report a double metamagnetic transition in Sr3Ru2O7 detected by magnetization and magnetic torque measurements. In addition to the reported metamagnetic transition [R. S. Perry, L. M. Galvin, S. A. Grigera, L. Capogna, A. J. Schofield, A. P. Mackenzie, M. Chiao, S. R. Julian, S. I. Ikeda, S. Nakatsuji, Y. Maeno, and C. Pfleiderer, Phys. Rev. Lett. 86, 2661 (2001)], an unexpected second transition started to appear in the higher-field region below 2 K, exhibiting stronger anisotropy between inter- and intraplane field directions. We shall discuss metamagnetism of Sr3Ru2O7 based upon spin-fluctuation theory as well as possible origins of the second metamagnetic transition.