High Pressure studies of the magnetic phase transition in MnSi: revisited

New measurements of AC magnetic susceptibility and DC resistivity of a high quality single crystal MnSi were carried out at high pressure making use of helium as a pressure medium. The form of the AC magnetic susceptibility curves at the magnetic phase transition suddenly changes upon helium solidification. This implies strong sensitivity of magnetic properties of MnSi to non hydrostatic stresses and suggests that the early claims on the existence of a tricritical point at the phase transition line are probably a result of misinterpretation of the experimental data. At the same time resistivity behavior at the phase transition does not show such a significant influence of helium solidification. The sharp peak at the temperature derivative of resistivity, signifying the first order nature of the phase transition in MnSi successfully survived helium crystallization and continued the same way to the highest pressure.Comment: 4 pages, 6 figure

Peculiar behavior of the electrical resistivity of MnSi at the ferromagnetic phase transition

The electrical resistivity of a single crystal of MnSi was measured across its ferromagnetic phase transition line at ambient and high pressures. Sharp peaks of the temperature coefficient of resistivity characterize the transition line. Analysis of these data shows that at pressures to ~0.35 GPa these peaks have fine structure, revealing a shoulder at ~ 0.5 K above the peak. It is symptomatic that this structure disappears at pressures higher than ~0.35 GPa, which was identified earlier as a tricritical poin

THE SCIENTIST’S ACTIVITY HAS BEEN TAKEN OVER BY HIS FOLLOWERS

The article is dedicated to the memory of Professor O.V. Inshakov – a talented scientist, a great teacher, an authoritative leader and a great public figure. His books, publications continue to live. His ideas had been ahead of time, and they are still urgent now. The scientific research by О.V. Inshakov in the field of fundamental and applied problems of economic development shaped the academic interests of young researchers and prominent scientists for many years ahead and provided an opportunity to look at many scientific problems in a new way. In the present article, students, followers, colleagues and associates of O.V. Inshakov share their memories of joint work and scientific research carried out under his leadership

Lost Heat Capacity and Entropy in the Helical Magnet MnSi

The heat capacity of MnSi at B = 0 and B = 4 T was measured in the temperature range 2.5-100 K. To analyze the data, calculations of the phonon spectrum and phonon density of states in MnSi were performed. The calculated phonon frequencies were confirmed by means of inelastic neutron scattering. The analysis of the data suggests the existence of negative contributions to the heat capacity and entropy of MnSi at T andgt; T-c that may imply a specific ordering in the spin subsystem in the paramagnetic phase of MnSi.Original Publication:Sergei M Stishov, Alla E Petrova, Anatoly A Shikov, Thomas A Lograsso, Eyvas Isaev, Borje Johansson and Luke L Daemen, Lost Heat Capacity and Entropy in the Helical Magnet MnSi, 2010, PHYSICAL REVIEW LETTERS, (105), 23, 236403.http://dx.doi.org/10.1103/PhysRevLett.105.236403Copyright: American Physical Societyhttp://www.aps.org