FIZIKA A 7 (1998) 1, 11-16

MAGNETIC AND OPTICAL PROPERTIES OF AMMONIUM ACID PHTHALATE

MOHAMED GAAFAR

Physics Department, Faculty of Science, Alexandria University, Egypt

Received 12 August 1997; revised manuscript received 24 March 1998; Accepted 11 May 1998

Studies of the principal diamagnetic susceptibilities and refractive indices of ammonium acid phthalate (AAP) crystal of orthorhombic phase are reported. The two properties for the crystal axes a,b and c are of opposite order, i.e., c_a > c_b > c_c, while n_a < n_b < n_c. Their relations to the structure are offered. The crystal is magnetically unique and optically biaxial with a strong negative optical birefringence. The optical axial plane is parallel to the (010) plane and the molecular one is nearer to the (100) plane. The work gives information on the shape and orientation of the molecules within the unit cell.

PACS numbers: 75.20.Ck, 75.30.Gw, 78.20.Fm
UDC 537.622, 535.542, 535.581

Copyright by The Croatian Physical Society
For problems or questions please contact fizika@fizika.hfd.hr