Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Microkelvin thermometry with Bose-Einstein condensates of magnons and applications to studies of the AB interface in superfluid He
AU - Heikkinen, P. J.
AU - Autti, S.
AU - Eltsov, V. B.
AU - Haley, R. P.
AU - Zavjalov, V. V.
PY - 2014/6
Y1 - 2014/6
N2 - Coherent precession of trapped Bose-Einstein condensates of magnons is a sensitive probe for magnetic relaxation processes in superfluid He-B down to the lowest achievable temperatures. We use the dependence of the relaxation rate on the density of thermal quasiparticles to implement thermometry in He-B at temperatures below K. Unlike popular vibrating wire or quartz tuning fork based thermometers, magnon condensates allow for contactless temperature measurement and make possible an independent in situ determination of the residual zero-temperature relaxation provided by the radiation damping. We use this magnon-condensate-based thermometry to study the thermal impedance of the interface between A and B phases of superfluid He. The magnon condensate is also a sensitive probe of the orbital order-parameter texture. This has allowed us to observe for the first time the non-thermal signature of the annihilation of two AB interfaces.
AB - Coherent precession of trapped Bose-Einstein condensates of magnons is a sensitive probe for magnetic relaxation processes in superfluid He-B down to the lowest achievable temperatures. We use the dependence of the relaxation rate on the density of thermal quasiparticles to implement thermometry in He-B at temperatures below K. Unlike popular vibrating wire or quartz tuning fork based thermometers, magnon condensates allow for contactless temperature measurement and make possible an independent in situ determination of the residual zero-temperature relaxation provided by the radiation damping. We use this magnon-condensate-based thermometry to study the thermal impedance of the interface between A and B phases of superfluid He. The magnon condensate is also a sensitive probe of the orbital order-parameter texture. This has allowed us to observe for the first time the non-thermal signature of the annihilation of two AB interfaces.
KW - Superfluid He-3
KW - Magnons
KW - BEC
KW - Coherent spin precession
KW - Spin diffusion
KW - Thermometry
KW - Quasiparticle impedance
KW - AB interface
KW - B PHASE-BOUNDARY
KW - MAGNETIC-FIELD
KW - SPIN-DIFFUSION
KW - HYDROSTATIC THEORY
KW - VIBRATING-WIRE
KW - HE-3-B
KW - TEXTURES
KW - VORTEX
KW - NMR
KW - TEMPERATURE
U2 - 10.1007/s10909-014-1173-x
DO - 10.1007/s10909-014-1173-x
M3 - Journal article
VL - 175
SP - 681
EP - 705
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
SN - 0022-2291
IS - 5-6
ER -