Fundamentals of Solid-State Phase Transitions, Ferromagnetism and Ferroelectricity
Author: Yuri Mnyukh
ISBN-13: 978-0759602182
Year: 2001
Publisher: 1st Books Library
Dr. Mnyukh starts his treatise of the above title by quoting from Charles Dickens’ Pickwick Papers. “The seventeen learned societies unanimously voted the presumptuous Blotton an ignorant meddler...”. Dr. Mnyukh then writes a very presumptuous book, covering the three seaparate areas of phase transitions, ferromagnetism, and ferroelectricity in a unified way. As to ferromagnetism, his main point is that the Weiss molecular theory/ Heisenberg exchange energy theory of ferromagnetism is wrong! He replaces the conventional theory with a theory depending on the effect of the crystal field, and nucleation-and-growth phase transitions. Among his particulars is (1) the “sigmoid” shape of hysteresis loops is due to the balance between the increase in nucleation sites and the decrease in the amount of the original phase; (2) the Bloch wall between magnetic domains is meaningless, but is a structural twin interface having zero thickness; and (3) the Curie point is not a “critical’ point and it is not a second-order transition! Instead it is a first-order transition and is due to nucleation and growth. The fundamentals of magnetism is not at issue - atoms, spins, spin-orbits, etc. “Existence of the ‘molecular field’ is the principal point of the theory of ferromagnetism; its nonexistence is the principal point of the current presentation.” Ferromagnetism is due to magnetic moments on atoms in crystals, ferroelectricity is due to is due to electric dipoles on atoms in crystals. Ferromagnets and ferroelectrics are treated in analogous ways and are referred to as “ferroics” by the author. An interesting feature of the book is a listing in Appendix V various comments from experts in ferromagnetism drawing attention to difficulties with the standard theory. As an example is a long series of quotes from Feynman, e.g. “The most recent calculations of the energy between the two electron spins in iron... still give the wrong sign.”
