We report the synthesis of a family of ferrimagnetic NiFe layered double hydroxides (LDHs) with a variable Ni2+/Fe3+ in-plane composition of [Ni1-xFex(OH)(2)]-(CO3)(x)/(2)center dot yH(2)O (x = 0.20, 0.25, and 0.33) by following a modified homogeneous precipitation. These layered magnets display high crystallinity, homogeneous hexagonal morphologies, and micrometric size that enable their quantitative exfoliation into single layers by sonomechanical treatment of the solids in polar solvents This was confirmed by dynamic light scattering,. UV-vis spectroscopy, high resolution transmission. electron microscopy, and atomic force. microscopy methodologies to study the resulting steady suspensions. Our magnetic study reflects that the iron content in the LDH layers controls the overall magnetism of these lamellae. Hence, the gradual replacement of Ni2+ with Fe3+ centers introduces a larger amount of " antiferromagnetically coupled Fe OH Fe pairs across the layers, provoking that the compound with the highest Fe/Ni ratio displays spontaneous magnetization at higher temperatures (T-irr = 15.1 K) and the hardest coercive field (3.6 kG). Mossbauer spectroscopy confirms that the cation distribution in the layers is not random and reflects the occurrence of Fe clustering due to. the higher affinity of Fe3+ ions to accommodate other homometallic centers in their surroundings. In our opinion, this clarifies the origin of the glassy behavior, also reported for other magnetic LDHs, and points out spin frustration as the most likely cause.