Dependence of the Curie temperature of tetrakis-(para-tetradecyloxy-phenyl)-porphyrinatomanganese (III)-tetracyanoethenide (Mn-OC 14-TCNE) on hydrostatic pressure to 21 kbar
Abstract
The dependence of the Curie temperature on hydrostatic pressure has been determined to 21 kbar for the ferromagnetic molecular magnet (Mn(OC 14H 29) 4(TCNE), where Mn III-ions are situated in ferrimagnetic porphyrin chains separated by 31.2 Å. In the present experiments both He-gas and piston-cylinder pressure systems are used to 6 and 21 kbar, respectively. Following an initial rapid decrease of the Curie temperature Tc with applied pressure from 20 to 15 K at 1.5 kbar, Tc abruptly begins to increase with pressure at an equally rapid rate, ultimately reaching nearly 37 K at 21 kbar. The change in the sign in d Tc/d P at 1.5 kbar is likely the result of a phase transition in the spin and/or lattice system. The possible role of dipolar interactions in determining the magnetic state in a system of parallel ferrimagnetic chains is discussed.
- Publication:
-
Journal of Magnetism and Magnetic Materials
- Pub Date:
- June 2001
- DOI:
- 10.1016/S0304-8853(01)00132-9
- Bibcode:
- 2001JMMM..231..172M