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The approach advanced by Harrison puts in the spotlight the fundamental role of bistability in hysteresis modeling. The description is based on physical premises concerning irreversible thermodynamics. In the original model, the upscaling of irreversible phenomena acting on the micromagnetic level is carried out by the introduction of a phenomenological parameter β. In the present paper, an alternative approach is proposed. The outputs of individual outputs of elementary hysteresis units (hysterons) are considered like in the stop model. A verification of the proposed model is carried out using measurement data for a praseodymium–dysprosium ribbon sample and a cylinder core made of cobalt-based amorphous material. [ABSTRACT FROM AUTHOR]

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Magnetic properties of hard magnets are currently attracting a great deal of attention. In the paper, the modified Harrison model was used to describe the saturating hysteresis loops of three praseodymium–dysprosium ribbons that differed in their chemical composition and processing conditions. Microstructural studies (TEM and diffraction patterns) were performed for the ribbons under consideration. The Harrison model incorporates a number of physically tangible concepts such as the anhysteretic curve, bifurcations, and bi-stability. The modification of the original approach consisted of adding an additional degree of freedom in the modeling by freeing the restraints present in the original version, in which both coercivity and remanence are functions of temperature only. [ABSTRACT FROM AUTHOR]

The hysteresis description advanced by Harrison is static in nature. On the other hand, it seems crucial for some applications to consider how the dynamic effects due e.g. to eddy currents in conductive materials affect the shapes of modeled hysteresis loops. In the paper two possible model extensions are proposed. The approach based on the introduction of an additional term in the so-called effective field yields a better accuracy in comparison to the extension using a term related to relaxation time. • The quasi-static hysteresis description based on positive feedback mechanism is extended to the dynamical case. • Two possible model extensions are compared. • The approach based on the introduction of a damping term into the so-called effective field yields a better accuracy. [ABSTRACT FROM AUTHOR]

The paper presents a new approach to modeling of magnetic properties and the influence of temperature on hysteresis loops in La(FeCoSi)13 magnetocaloric compound. The GRUCAD hysteresis model has been used for analysis of magnetic behavior in the vicinity of the magnetic phase transition. The modeling results are in a qualitative agreement with experiment. [ABSTRACT FROM AUTHOR]

• The scaling analysis of phase transitions in magnetocaloric alloys (MCA) is validated. • The scaling exponent values change significantly near phase transition temperatures. • The scaling exponent characteristics indicate an additional phase transition at 315 K. • This is an alternative method for determining phase transition temperatures in MCA. • The method allows one to determine hardly noticeable phase transitions. The paper presents magnetization measurements and the scaling analysis of related power loss for a high-temperature magnetocaloric alloy (T C = 330 K). The measured hysteresis loops show anomalous behaviour near the temperature of 315 K, which may indicate the occurrence of additional phase transition. Power losses measured in different temperatures are analyzed using the scaling theory in order to determine the universal curves and the scaling exponents. The temperature dependence of scaling exponents confirms the existence of another phase transition at the temperature of 315 K, associated with an additional metallic phase in the alloy. [ABSTRACT FROM AUTHOR]

In the present paper, the effect of temperature on the shape of magnetic hysteresis loops for a magnetocaloric composite core was studied. The composite core, based on La(Fe, Mn, Si)13-H, was set up using three component disks with different Curie temperatures. The magnetic properties of the components and the outcome composite core were determined using a self-developed measurement setup. For the description of hysteresis loops, the phenomenological T(x) model was used. The presented methodology might be useful for the designers of magnetic active regenerators. [ABSTRACT FROM AUTHOR]