2004/01/09 by B. Sales, Brian Sales, R. Jin +6
Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0401154
arxiv created 2004/01/09 · openalex publication_date 2004/01/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The ability of an insulating solid to conduct heat is rarely effected by the application of a magnetic field. We have found, however, that the low temperature heat conduction of some solids increases by more than a factor of two with the application of a modest magnetic field. The effect occurs in low-dimensional magnetically ordered materials when a small gap, δ, in the acoustic magnon (spin wave) spectra is closed using a magnetic field H > δ/gμB. Since all magnetically ordered materials must have a gap in the magnon spectra for magnons with k = 0, this may be a very general effect. Extra heat is carried through the solid only when the magentic field exceeds the critical value (H > δ/gμB). At this critical field the tiny atomic magnets in the solid abruptly change the direction they point which results in more heat flowing through the material. The magnetic field thus acts as a heat switch. We have observed this effect in three quite different magnetically ordered materials: K2V3O8, Nd2CuO4 and Pr2CuO4. Several possible explanations for these effects will be discussed.