Ising-type Magnetic Anisotropy in CePd2As2

We investigated the anisotropic magnetic properties of CePd2As2 by magnetic, thermal and electrical transport studies. X-ray diffraction confirmed the tetragonal ThCr2Si2-type structure and the high-quality of the single crystals. Magnetisation and magnetic susceptibility data taken along the different crystallographic directions evidence a huge crystalline electric field (CEF) induced Ising-type magneto-crystalline anisotropy with a large c-axis moment and a small in-plane moment at low temperature. A detailed CEF analysis based on the magnetic susceptibility data indicates an almost pure vertical bar +/- 5/2 > CEF ground-state doublet with the dominantly vertical bar +/- 3/2 > and the vertical bar +/- 1/2 > doublets at 290 K and 330 K, respectively. At low temperature, we observe a uniaxial antiferromagnetic (AFM) transition at T-N = 14.7 K with the crystallographic c-direction being the magnetic easy-axis. The magnetic entropy gain up to T-N reaches almost R ln 2 indicating localised 4 f-electron magnetism without significant Kondo-type interactions. Below T-N, the application of a magnetic field along the c-axis induces a metamagnetic transition from the AFM to a field-polarised phase at mu H-0(c0) = 0.95T, exhibiting a textbook example of a spin-flip transition as anticipated for an Ising-type AFM.