Paramagnetic limit of superconductivity in a crystal without inversion center

The theory of paramagnetic limit of superconductivity in metals without inversion center is developed. There is in general the paramagnetic suppression of superconducting state. The effect is strongly dependent on field orientation in respect to crystal axes. The reason for this is that the degeneracy of electronic states with opposite momenta k and −k forming of Cooper pairs is lifted by magnetic fields but for some field directions this lifting can be small or even absent. Quite recently the first unconventional superconductors without inversion symmetry CeP t 3 Si [1] and UIr [2] have been discovered. The former reveals superconductivity in antiferromagnetic state [3] while the second is a ferromagnetic superconductor. The microscopic theory of superconductivity in metals without inversion has been developed by V.Edel'stein [4] pretty long ago. The different aspects of theory of superconductivity in such type materials has been discussed about the same time [5–7] and has been advanced further in more recent publications [8–15]. Finally, the general symmetry approch to the superconductivity in the materials with space parity violation has been developed [16,17]. Particular attention has been attracted to the question about paramagnetic limit in such type materials [15]. It was occured that zero temperature upper critical field in polycrystill