ABSTRACT
We report the magnetic and electrical characteristics of polycrystalline FeTiO_{3} synthesized at high pressure that is isostructural with acentric LiNbO_{3} (LBO). Piezoresponse force microscopy, optical second harmonic generation, and magnetometry demonstrate ferroelectricity at and below room temperature and weak ferromagnetism below approximately 120 K. These results validate symmetry-based criteria and first-principles calculations of the coexistence of ferroelectricity and weak ferromagnetism in a series of transition metal titanates crystallizing in the LBO structure.
ABSTRACT
We have examined the presentation of low back pain in three patients with ochronosis, and have reviewed the literature. Low back pain and/or stiffness is the first presenting feature and usually appears after the age of 30. Discolouration of the ear is almost always present. Characteristic radiographic changes in the lumbar spine include calcification of the intervertebral discs and lucencies in the discs. The process gradually extends to the entire spine.
