ИСТИНА

The researching of neutron and electron diffraction and magnetic properties of Sm0.5.5Sr0.45MnO3 have shown that there is a magnetic inhomogeneous state in it consisting of ferromagnetic (F) clusters with Curie point TC=134 K, A-type antiferromagnetic (AF) clusters with Neel temperature TNA~TC and CE-type AF clusters with TNCE=240K. We have investigated the thermopower a and longitudinal magnetothermopower delta a/a of the monocrystalline Sm05.5Sr0.45MnO3 in magnetic field up to 13.2 kOe. Single crystal was grown by the floating-zone method. and was annealed in oxygen. The annealing in oxygen closes broken connection Mn-V-Mn (V is vacancy) and CE-type AF phase becomes dominant in the sample. The broad maximum on the curves of temperature dependences α(T) includes TNCE, whereas the giant minimum on the {delta a/a}(T) curves is sharp and is located near the TNCE. As it shown earlier the imposition of magnetic field H>8 kOe at T>TC on this sample transfers CE-type AF state in F state in the jumplike fashion. Sharp decrease of α in TNCE under the action of magnetic field is connected to destruction of CE-type AF phase and also connected with its charge order displacing oxygen ions. Electrical current, flowed in the sample at an α-measurement, causes Peltier effect on boundary of CE-type AF cluster and a temperature difference ∆T arises on this cluster. Internal thermopower is caused by influence of aT and equals to (a1-a2)deltaT, where a1 is the thermopower of cluster. Sharp decrease of crystal’s thermopower in TNCE-region shows a big contribution in it from AF CE-type clusters. Thereby magnetic inhomogeneity combined with strongly structural heterogeneity influences on thermopower and magnetothermopower in Sm0.55Sr0.45MnO3. The value of thermopower may be regulated by magnetic field. Thus, opens up new perspectives to the researching of similar big thermopower nanomaterials that can be used in environmentally friendly voltage generators.