In this work we have researched the features of dynamic magnetoelectric and magnetoelastic interactions in multiferroic crystal, influenced by various external fields, with the group of symmetry. Based on the integrated approach, which combines N. N. Bogolyubov’s quantum-statistic methods, Green’s temperature functions, diagram technique and symmetry, energy spectrum’s and static spin susceptibility’s dependences on the temperature and external fields were calculated. The effective parameters of magnetoelectric and magnetoelastic interactions dependences on the external fields’ intesities were analysed. It is shown that these parameters have a distinct maximum in the resonance value. As was shown, it is possible to enhance the interactions between spins, ferroelectric and fonons subsystems in multiferroics by applicating the external fields in different crystallographic directions. Multiferroics, which include a number of alloys and compounds, are quite promising materials for creating functional parts of modern microand nanoelectronic devices. Therefore, an interest for analysis of model ferroelectromagnetic systems with strongly correlated elastic, magnetic and ferroelectric subsystems has increased nowadays [1, 2]. In this work we have researched the features of dynamic magnetoelectric and magnetoelastic interactions in multiferroic crystal, influenced by various external fields, with the group of symmetry, which is taken into consideration when invariants in the Hamiltonian are being chosen. In these crystals exist strong correlations between elastic, magnetic and ferroelectric subsystems [1, 2], which causes their uniqueness as experimental and theoretical research object and, more importantly, materials with ample possibilities of applying as microand nanostructural elements of modern microelectronics and adjacent area of technology.

Потребности науки и современной техники активизируют поиск, синтез и исследование материалов, обладающих уникальными физическими свойствами. Весьма перспективными для создания функциональных элементов современной микроэлектроники являются мультиферроики - структуры типа перовскита, симметрия которых допускает одновременное существование в определенном интервале температур магнитного и сегнетоэлектрического дальнего порядка. В работе определены полевые и температурные зависимости намагниченности и энергетического спектра мультиферроика с линейным по внешнему электрическому полю магнитоэлектрическим эффектом. С помощью диаграммной техники определен вклад в свободную энергию за счет динамического взаимодействия спиновых волн, зависимость этого вклада от внешних магнитного и электрического полей и температуры.