Heat capacity measurements on manganese dibromide tetrahydrate near its Neel temperature

Heat capacity measurements on very small single crystals of manganese dibromide tetrahydrate have been made using the a.c. or oscillating temperature method. These measurements show rounding in a temperature range of about one millidegree at the Neel temperature (2.l2oK). Outside this region the data may be fit by a power law singularity, within the experimental error, with 0.01 < alpha < 0.21, -0.10 < alpha' < 0.10 and 2.ll88°K < TN < 2.1204°K. The errors in ~, ~', and TN were obtained from a chi squared test for 90% probability that the true values lie within these limits. The heat capacity in the critical region of partially deuterated crystals with 1% deuterium was measured to obtain the effect of this impurity on the rounding. No effect was observed. Comparison is made to the heat capacity measurements by Dixon and Rives on MnC12 .4H20, which is nearly isostructural to MnBr2·4H20.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Hempstead, Robert Douglas

Contributors dc:contributor

• Mochel, J.M.

• heat capacity
• manganese dibromide tetrahydrate
• Neel temperature

Statement dc:rights

• 1970 Robert Douglas Hempstead

Language dc:language

en

Identifier

6053223

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25866