Magnetic Properties of 4f Localized Ferromagnet CeAgSb^sub 2^ under Transverse Magnetic Fields

We performed dc-magnetization and ac-susceptibility measurements to clarify how the magnetic properties of CeAgSb2, which shows ferromagnetic order along the c-axis below 9.6 K, evolve with the application of a transverse magnetic field (Hab). The Curie temperature (TC) is suppressed to zero by the application of Hab, and the ac-susceptibility measured along the c-axis ?'c?c' under Hab continuously shows a critical-divergence-like anomaly at TC, indicating the presence of a field-induced ferromagnetic quantum critical point in this compound. On the other hand, the magnitude of ?'c?c' at TC rapidly decreases with increasing Hab up to around 0.5 T. This result suggests that the magnetic properties around TC rapidly change with Hab in the relatively lower Hab range.