Low Temperature Heat Capacity of polycrystalline MnSi

International Conference on Recent Trends in Physics 2016

Mishra, Ashish^1 ; Krishnan, M.^1 ; Gangrade, Mohan^1 ; Singh, Durgesh^1 ; Venkatesh, R.^1 ; Ganesan, V.^1

UGC-DAE Consortium for Scientific Research, Indore, MP

452001, India^1

关键词: Low temperature heat capacities;    Magnetically ordered state;    Polycrystalline;    Relaxation calorimetry;    Sommerfeld coefficient;    Spin-wave spectrum;    Spinwave excitation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/755/1/012037/pdf
DOI  :  10.1088/1742-6596/755/1/012037

来源: IOP

【 摘 要 】

The itinerant helimagnet MnSi has been investigated by heat capacity using relaxation calorimetry in H=0. The paramagnetic to helimagnetic transition temperature Tc is found to be 29.6 K. Low temperature heat capacity data in the range 2-18 K is fitted with a usual electronic and phonon contribution. However, an additional magnetic term T3/2needs to be added to witness the role of spin wave excitations in the magnetically ordered state below Tc. As well the energy gap on the order A=1.29 meV in the spin wave spectrum is evidenced. Small value of magnetic coefficient δ = 1.66 mJmol-1K-5/2hints the itinerant nature of the magnetism in MnSi. Obtained coefficients gives the Debye temperature θD= 534 K and the Sommerfeld coefficient of specific heat γ = 0.0367 Jmol-1K-2. Noteworthy observation is the negative trend in the magnetic part of the entropy after Tc.