Magnetic phase transitions in multiferroic bismuth ferrite (BiFeO3) induced by magnetic field, epitaxial strain, and composition modification are considered. These transitions from a spatially modulated spin spiral state to a homogenous antiferromagnetic one are accompanied by the release of latent magnetization and a linear magnetoelectric effect that makes BiFeO3-based materials efficient room-temperature single phase multiferroics.Since the beginning of the multiferroic era (in the early 1960s), after Soviet scientists discovered a new class of materials that was called "ferroelectromagnets" [1], to our present time, bismuth ferrite BiFeO 3 has remained the prototypical example of a multiferroic: having a relatively simple structure and at the same time quite diversified and uncommon properties.On the one hand due to its simple chemical and crystal structure, BiFeO 3 is a model system for fundamental and theoretical studies of multiferroics [2]. However, on the other hand, its unusual magnetic symmetry properties (space and time symmetry violation both in its crystal and magnetic structures) results in a variety of nontrivial consequences, including: (i) the unique coexistence of weak ferromagnetism and linear magnetoelectricity [3,4]; (ii) a toroidal moment, i.e., a special magnetic type of ordering [5][6][7][8]; (iii) the existence of an incommensurately modulated spin structure [9], previously only observed in magnetic metals; and (iv) magnetically induced optical second harmonic generation, observed for the first time in this particular material [10]. Furthermore, BiFeO 3 is the material with unique high ferroelectric Curie (T C =1083 K) [11] and antiferromagnetic Neel (T N =643K) [12] temperatures. However, its potential has yet to be realized, and might never be fully exploited. Difficulties persist as the magnetoelectric exchange and weak ferromagnetism are locked within a spin cycloid. A fundamental problem is that electronic configurations that favor magnetism are antagonistic to those that favor polarization [2] -compromise is necessary. Recently, investigations have shown that the multiferroic properties of BiFeO 3 can be dramatically increased by (i) epitaxial constraint [13], and/or (ii) rare earth substituents. These findings coupled with those in ME two-phase (nano and macro) composites of piezoelectric and magnetostrictive materials have served as triggers for a "magnetoelectric renaissance": the revival of hope to find a room temperature magnetoelectric material with significant coupling of polar and magnetic subsystems [14][15][16]. As a consequence, multiferroics are now being considered as promising materials for spintronics [17,18], magnetic memory systems, sensors, and tunable microwave devices [19]: offering the potential to revolutionize electromagnetic material's applications.