[1] Czech Acad Sci, Inst Phys, Na Slovance 2, Prague 18221 8, Czech Republic
[2] Czech Tech Univ, Fac Nucl Sci & Phys Engn, Brehova 7, Prague 11519 1, Czech Republic
[3] Budapest Univ Technol & Econ, Dept Phys, H-1111 Budapest, Hungary
[4] MTA BME Lendulet Magnetoopt Spect Res Grp, H-1111 Budapest, Hungary
[5] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
[6] Chongqing Univ, Dept Appl Phys, Chongqing 401331, Peoples R China