TEMPERATURE-DEPENDENCE OF THE DOMAIN-STRUCTURE IN FE14ND2B SINGLE-CRYSTALS DURING THE SPIN-REORIENTATION TRANSITION

The temperature dependence of the magnetic domain structure of Fe14Nd2 B single crystals is investigated from room temperature down to 4.2K b y means of the magneto-optical Kerr effect. The parallel stripe domain structure characteristic of high-anisotropy uniaxial ferromagnets is observed on the (h k 0) planes of the crystals at room temperature. Th is structure remains practically unchanged down to about 140 K. In the vicinity of the magnetic phase transition at T-SR = 135 K the domain structure undergoes intense realignment. Below T-SR a new type of doma in structure occurs being characterized by a periodic modulation of th e magnetization orientation inside the main domains together with a de veloped system of closure domains having different preferential orient ations. For the particular sample studied the width of the main domain s at 4.2 K is about 100 mu m, while that of closure domains is about 2 -5 mu m.