Multicritical end point of the first-order ferromagnetic transition in colossal magnetoresistive manganites.
We have studied the bandwidth-temperature-magnetic-field phase diagram of RE0.55Sr0.45MnO3 colossal magnetoresistance manganites with ferromagnetic metal (FM) ground state. The bandwidth was controlled both via chemical substitution and hydrostatic pressure with a focus on the vicinity of the critical pressure p;{*} where the character of the zero-field FM transition changes from first to second order. Below p;{*} the first-order FM transition extends up to a critical magnetic field. It approaches zero on the larger bandwidth side where the surface of the first-order FM phase boundary is terminated by a multicritical end point. The change in the character of the transition and the decrease of the colossal magnetoresistance effect is attributed to the reduced charge-order and orbital-order fluctuations.
Demkó
L
L
Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, 1111 Budapest, Hungary.
Kézsmárki
I
I
Mihály
G
G
Takeshita
N
N
Tomioka
Y
Y
Tokura
Y
Y