Twenty one years ago, the discovery of the giant magnetocaloric effect (GMCE) at room temperature completely revolutionized the magnetocaloric materials fi

We investigate the magnetocaloric effect dependency on the most important microscopic parameters of ferromagnetic materials, such as the Curie temperature (TC), the spin value (J), and the magnetic field change (ΔH). Second- and first-order phase transition systems are considered, using the Bean-Rodbell model [C. P. Bean and D. S. Rodbell, Phys. Rev. 126, 104 (1962)] of magnetovolume interactions on the Weiss mean-field model [P. Weiss, J. Phys. Theory Appl. 6, 661 (1907)]. The magnetocaloric effect simulations show a surprising TC−2/3 linear dependence of the maximum entropy change (ΔSmmax), which is observed for all simulated systems. An approximate state equation establishing the dependence of ΔSmmax on TC, ΔH, J, and the magnetic atoms density (N) is presented. The dependence of maximum magnetic entropy change on TC−2/3 is validated by a wide set of experimental results of second- and first-order phase transition materials that are promising for magnetic refrigeration applications at room temperature.

Colorectal cancer is the third most common cancer worldwide. Despite recent advances in the treatment of this pathology, which include a personalized approach using radio- and chemotherapies in combination with advanced surgical techniques, it is imperative to enhance the performance of these treatments and decrease their detrimental side effects on patients’ health. Nanomedicine is likely the pathway towards solving this challenge by enhancing both the therapeutic and diagnostic capabilities. In particular, plasmonic nanoparticles show remarkable potential due to their dual therapeutic functionalities as photothermal therapy agents and as radiosensitizers in radiotherapy. Their dual functionality, high biocompatibility, easy functionalization, and targeting capabilities make them potential agents for inducing efficient cancer cell death with minimal side effects. This review aims to identify the main challenges in the diagnosis and treatment of colorectal cancer. The heterogeneous nature of this cancer is also discussed from a single-cell point of view. The most relevant works in photo- and radiotherapy using nanotechnology-based therapies for colorectal cancer are addressed, ranging from in vitro studies (2D and 3D cell cultures) to in vivo studies and clinical trials. Although the results using nanoparticles as a photo- and radiosensitizers in photo- and radiotherapy are promising, preliminary studies showed that the possibility of combining both therapies must be explored to improve the treatment efficiency.

The static magnetization and dynamic susceptibility responses of the cluster system within a Griffiths phase of the magnetocaloric compound ${\mathrm{Tb}}_{5-x}{\mathrm{La}}_x{\mathrm{Si}}_2{\mathrm{Ge}}_2$ ($x=0.075$) have been investigated. A novel cluster-glass state within the Griffiths phase is formed at a characteristic freezing temperature where short-range ferromagnetic correlations set in the paramagnetic regime. Ferromagneticlike correlations are built up at around 155 K, which suddenly become frozen at a lower temperature $\sim 140\mathrm{K}$, thus in analogy with a reentrant spin glass behavior. The ac susceptibility near the freezing temperature follows a critical slowing down process characterized by ${\tau }_0={10}^{-13}s$ and dynamic exponents $\mathrm{z}\nu \sim 6$ and $\beta \sim 0.4$, similar to well-known spin glass systems. The nonlinear ac susceptibility analysis shows clearly the existence of a transition associated to the reentrant behavior. The origin of the intermediate cluster-glass phase inside the Griffiths phase is proposed to be the result of a combination of short-ranged RKKY intralayer positive exchange interactions between rare-earth ${\mathrm{Tb}}^{3+}$ ions and antiferromagnetic exchange between adjacent interlayers involving Si and Ge atoms in connection to the ${\mathrm{Tb}}^{3+}$ atoms.

Magnetic refrigeration based on the magnetocaloric effect is one of the best alternatives to compete with vapor-compression technology. Despite being already in its technology transfer stage, there is still room for optimization, namely, on the magnetic responses of the magnetocaloric material. In parallel, the demand for different magnetostrictive materials has been greatly enhanced due to the wide and innovative range of technologies that emerged in the last years (from structural evaluation to straintronics fields). In particular, the Gd₅(Si_xGe_1−x)₄ compounds are a family of well-known alloys that present both giant magnetocaloric and colossal magnetostriction effects. Despite their remarkable properties, very few reports have been dedicated to the nanostructuring of these materials: here, we report a ∼800 nm Gd₅Si_2.7Ge_1.3 thin film. The magnetic and structural investigation revealed that the film undergoes a first order magnetostructural transition and as a consequence exhibits large magnetocaloric effect (−ΔS_mMAX ∼ 8.83 J kg⁻¹ K⁻¹, ΔH = 5T) and giant thermal expansion (12000 p.p.m). The thin film presents a broader magnetic response in comparison with the bulk compound, which results in a beneficial magnetic hysteresis reduction. The ΔS_mMAX exhibited by the Gd₅(Si,Ge)₄ thin film makes it a promising candidate for micro/nano magnetic refrigeration area.