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Al-Cu-Fe based quasicrystal thin films exhibit unique surface and mechanical properties. To better understand the formation of the quasicrystal thin films, we observe direct growth of quasicrystals, prepared in a multilayer Al-Cu-Fe thin films with subsequent heat treatment, by in-situ synchrotron x-ray diffraction and in-situ transmission electron microscopy during heating and cooling. Using these two methods, we show that the ternary phase is more thermodynamically stable compared to the binary phases at temperature higher than 470 °C during the heating process, and quasicrystal formation occurs during the cooling process, specifically at 660 °C, after the sample has reached a liquid state. To distinguish quasicrystal from approximant crystals in the obtained thin film samples, we use high resolution x-ray diffraction to analyze the sample at room temperature. We reveal that the peak broadening increases monotonically along the twofold, threefold, and fivefold high-symmetry directions with the physical scattering vector but does not have systematic dependence on the phason momentum, which suggests that the thin film sample is indeed a quasicrystal instead of approximant crystals and it is almost free of phason strain. Our study provides a complete understanding of the growth mechanism for thin film Al-Cu-Fe quasicrystals, which is of particular importance for developing versatile applications of quasicrystal thin films. Image 1 [ABSTRACT FROM AUTHOR]

We demonstrate a simple approach to fabricate Cu 2 ZnSn(S, Se) 4 (CZTSSe) absorber with increased-sulfur content surface. It is well known that the problem of interface recombination in CZTSSe solar cells is the issue for further improving efficiency. The beneficial effects of surface sulfurization were reported in Cu(In, Ga)(S, Se) 2 solar cells. However, very limited works have been reported on the effects of surface sulfurization on CZTSSe solar cells, which is a critical factor to improve the surface and achieve higher efficiency. In this work, we fabricate the CZTSSe absorber by selenizing the sulfur-containing stacked precursors. The sulfur-modified surface is achieved by introducing H 2 S gas during cooling stage of the selenization process. The effects of surface sulfurization on composition, structure, morphology, and electric properties of CZTSSe are thoroughly investigated. The open circuit voltage can be increased significantly from 312 mV (without H 2 S) to 400 mV (with H 2 S) due to the increment of front surface bandgap and reduction of interface recombination. Surface localized electric properties are improved, and interface defect density is decreased due to surface passivation by using H 2 S gas. The efficiency of CZTSSe solar cell substantially increases from 5.01% (without H 2 S) to 7.38% (with H 2 S). The proposed approach can be easily applied to various CZTSSe processes to passivate the surface and form larger surface bandgap, leading to lower interface recombination, which paves a new avenue to further improve the CZTSSe efficiency. [ABSTRACT FROM AUTHOR]

• An effective and efficient separation of tungsten and cobalt elements in WC-Co was realized via rapid breakdown anodization. • 99.99 wt% WO 3 -H 2 O was obtained, and 90.43 wt% Co metal was recovered at cathode via the one-step electrochemical approach. • Anodic passivation of WC-Co during electro-dissolution was resolved by the electrochemical breakdown of the oxidation film. • A new pathway for WC-Co recycling was proposed with a significantly simplified process compared to conventional methods. Cemented tungsten carbide (WC-Co) has been used as an important industrial material and secondary resource of tungsten (W) and cobalt (Co). The recycling methodology of WC-Co scraps has drawn much attention because the recovery of strategic metals such as W and Co are critical. Here, rapid breakdown anodization (RBA) was applied for the first time to the conversion of WC-Co into high-purity hydrated tungsten oxide (WO 3 -H 2 O) up to 99.99 wt% and pure Co metal up to 90.43 wt% by using WC-Co as a sacrificial anode. Effective cobalt leaching was achieved in acidic aqueous solution without encountering anodic passivation issue due to the successful removal of tungsten oxidation layer during the electro-dissolution of WC-Co. Based on the particle formation mechanism of RBA, a two-stage reaction was confirmed, including electrochemical dissolution and chemical precipitation. The high purity of recovered WO 3 -H 2 O powders was realized by using high current density and high electrolyte concentration. We demonstrate that RBA is a new pathway for effective and environmentally-friendly WC-Co recycling with a significantly simplified process compared to conventional hydrometallurgical methods. [ABSTRACT FROM AUTHOR]

• Spin-orbit torque (SOT) switching of the single CoTb layer is realized. • The generation of self-torque depends on the thickness of CoTb. • The switching polarity of single Co 70 Tb 30 is the same as Pt. • The switching efficiency can be varied in heavy metal/CoTb due to the interplay of SOT from heavy metal and CoTb. We investigated the spin–orbit torque (SOT) switching of the single CoTb layer with or without the heavy metals (Pt and W) in different thickness to identify the self-torque effects generated in the CoTb layer. The generation of self-torque heavily depends on the thickness of CoTb. The SOT switching was not observed for a single CoTb layer with 3 nm in thickness, suggesting self-torque may be quite weak in a very thin film. A deterministic SOT switching can be obtained for a single 9 nm CoTb layer. The amplitude of the self-torque generated in CoTb is comparable to the Co/Pt case with the same switching polarity as the Co/Pt one. When 3 nm CoTb was deposited on Pt or W underlayer, the J c is smaller in W/CoTb than that of Pt/CoTb, which can be attributable to a high spin hall angle of W and negligible self-torque of CoTb. On the other hand, when the CoTb is increased to 9 nm, the J c of W/CoTb is significantly increased and becomes higher than that of Pt/CoTb. The enhanced J c of W/CoTb may result from the opposite sign of spin orbit torque generated in W and CoTb. Since the self-torque generated in 9 nm CoTb becomes substantial, the competition of spin orbit torque between W and CoTb occurs, leading to a high J c. Our findings may shed light to utilize self-torque induced in rare earth-transition metal alloy for new design of SOT devices. [ABSTRACT FROM AUTHOR]

A two-step process with post-annealing of stacked precursors has been widely used for Cu 2 ZnSn(S,Se) 4 (CZTSSe) absorbers. However, no simple approach is currently available for simultaneously tuning the S/(S+Se) ratio and avoiding tin loss issue in CZTSSe films, which are critical factors to achieve high efficiency. In this work, we demonstrate by simply adding SnS powder during selenization, we can eliminate the tin loss and also control the S/(S+Se) ratio. Furthermore, we can suppress the formation of Mo(S,Se) 2 during selenization. Based on thermodynamic calculations, we propose SnS powder reacts with selenium to form SnSe and releases sulfur vapor during selenization. The Sn-contained vapor avoids tin evaporation from CZTSSe. By varying the amount of SnS powder, the partial pressure ratio of sulfur to selenium can be tuned; therefore, the film composition and band bap of CZTSSe can be changed. The presence of sulfur partial pressure also dramatically decreases the formation of Mo(S,Se) 2 during selenization. The efficiency is substantially boosted from 3.97% to 7.35% by adding SnS powder during selenization. Our approach realizes one-step sulfo-selenization, providing a general tuning knob for compositional control of CZTSSe absorbers, which shines light on various process developments of CZTSSe absorbers by post-annealing vacuum- or solution-fabricated precursors. [ABSTRACT FROM AUTHOR]

This study presents a magnetostrictive type inductive sensing pressure sensor which consisted of a planar coil, CoFeB magnetic films, and a Si diaphragm. As the Si diaphragm deformed by a pressure load, the inverse-magnetostriction effect would cause permeability changes of the CoFeB magnetic films. Thus, the permeability changes as well as the pressure load can be detected by the inductance change of a planar inductor. To demonstrate the feasibility of the proposed pressure sensor, the planar inductor designs of different coil turns and in-plane patterns of magnetic films are fabricated and tested. Preliminary measurements show that the pressure sensors with 6 and 12 coil turns have sensitivities of 0.079 %/kPa and 0.064 %/kPa, respectively. In addition, based on the in-plane pattern design of the magnetic films, the gauge factor could be tuned from 55 to 852. [ABSTRACT FROM AUTHOR]

A separation process for Cu, In, Ga, and Se (CIGS)-based thin-film solar panels is proposed in this study. Initially, the separation process, by peeling off the panels in a layer-by-layer manner, was achieved by utilizing the different thermal strains of materials inside the CIGS solar panels. Subsequently, the recovery process was performed by annealing the CIGS layers for the removal of Se, and then leaching was performed with nitric acid, followed by the individual extraction of valuable metals. The pH values, concentrations of extractant, stripping agents, organic-aqueous ratios, and reaction time were investigated in detail to optimize the separation conditions for Cu, In, and Ga. First, In was extracted using di-(2-ethylhexyl) phosphoric acid into the organic phase, while Cu and Ga remained in the aqueous phase, by controlling the extraction conditions. After the extraction of In, Ga was extracted using the same extraction agent under different conditions, and nearly pure Cu remained in the residual aqueous solution. Ammonium hydroxide was added to three solutions to form metal hydroxide precipitates. Under the optimal conditions, a recovery rate of >90% could be achieved for In, Ga, and Cu. Furthermore, all as-formed hydroxides were recycled and converted into metal oxides with a purity of >99% by calcination. These findings can provide a pathway for the effective recycling and recovery of Cu, In, and Ga from waste CIGS thin-film solar panels. [Display omitted] • A facile and practical method to separate and recover valuable metals respectively from the real commercial thin-film solar panel was demonstrated. • A novel and low-cost physical separation process was induced to peer off the solar panel layer by layer via the extremely low-temperature liquid nitrogen treatment. • An extraction and stripping process was designed to separate Cu, In, and Ga from a complicated multi-element system individually. • Highly pure valuable metal oxides were recovered as the final products, establishing a possible curcular economy model for waste solar panel recycling and recovery. [ABSTRACT FROM AUTHOR]

Abstract: Template-free, one step formation of Cu(In, Ga)Se2 (CIGS) nanotip arrays (NTRs) to enhance device efficiency were discussed. Through Ar+ ion milling process, the CIGS NTRs could be formed directly on the CIGS layer. The angles and lengths of CIGS NTRs could be precisely controlled by incident angle of Ar+ beam and milling time, respectively. Mechanisms were proposed to be a self-masking effect by Cu segregation formed at early stage confirmed by Transmission Electron Microscopy, Grazing Incidence X-ray Diffraction, Energy Dispersive Spectroscopy, and Auger Electron Spectroscopy. Measurements of devices on various KCN washing time and thickness of CdS buffer layer were reported to achieve the highest efficiency of CIGS NTRs devices. This approach provides one-step fast process without templates, easy integration with in-line sputtering process, and no post-selenizatoin process for the formation of CIGS nanostructure, which can stimulate great attention not only in academic investigations but also in industrial side for practical applications. [Copyright &y& Elsevier]

Abstract: The characteristics of the Cu-rich Cu(In,Ga)Se2 (CIGS) films prepared by one-step sputtering process from a single quaternary target have been studied. The influences of working pressure, substrate temperature, Mo back contact, and KCN treatment on the properties of CIGS films were investigated. Target stability has been in-situ monitored by using optical emission spectroscopy. Obvious compositional change due to the KCN effect was observed, while only slight variation was caused by working pressure. We found the preferred orientation and crystallinity of one-step sputtered CIGS films were affected by the working pressure and substrate temperature when CIGS were directly deposited on the glass substrates. However, for the device fabrication, Mo back contacts dominated the growth behavior of CIGS films and induced better crystallinity with larger CIGS grain sizes. To explore the electrical properties of CIGS films on Mo back contacts, we developed a simple two-point probe measurement to examine the conductive channels within CIGS films before the device fabrication. Finally, one-step sputtered CIGS devices showed the efficiency of more than 8% at the working pressure of 0.4–2.7Pa with KCN treatment. [Copyright &y& Elsevier]

Abstract: Many approaches had been reported to successfully reduce the transition temperature of FePt from A1 to L10 phase, though without detailed knowledge. In this work, we deposited the metastable AgPt layer adjacent to the Fe layer and addressed the importance of vacancies in the disorder–order transition of FePt at reduced temperatures on the basis of a kinetic diffusion model. The decomposition of the metastable AgPt phase, creating excess vacancies during the post-deposition annealing process, accelerated the intermixing between Fe and Pt and the nucleation of L10 FePt. The evolution of phase transformation from AgPt–Fe to L10 FePt–Ag was monitored by in situ high temperature X-ray diffractometry and was also validated by first-principles calculations. The intermixing between Fe and Pt and the nucleation of L10 FePt after annealing at 230°C were directly observed by transmission electron microscopy and grazing incidence X-ray diffractometry, respectively. With the assistance of the decomposition of AgPt, we obtained a (001)-dominated L10 FePt film with an out-of-plane coercivity as large as 13.3 kOe after annealing at a temperature as low as 350°C. The principles of the proposed method can be applied for versatile disorder–order phase transitions. [Copyright &y& Elsevier]

Abstract: One-step fabrication of the chalcopyrite Cu(In,Ga)Se2 (CIGS) absorber layer without excess Se supply during/after deposition or post-selenization treatments is reported. By using pulse DC sputtering from a single quaternary CIGS target, the chalcopyrite structure is spontaneously developed on the substrate at 500°C even without extra Se supply. The obtained CIGS absorber layer possesses columnar grains with (112) preferred orientation. Device efficiency of 8.22% is observed for slightly Se-deficient CIGS films. By further tuning the target composition, the efficiency is enhanced to 10.14%. We demonstrate that the device-quality CIGS absorber can be formed even in the Se-deficient environment and further improvement of efficiency can be achieved by tuning the Se content of the target. Accordingly, our one-step sputtering process shows great potential for mass production of thin film CIGS solar cells with a low cost and a high throughput. [Copyright &y& Elsevier]

Terahertz (THz) spin dynamics and vanishing stray field make antiferromagnetic (AFM) materials the most promising candidate for the next-generation magnetic memory technology with revolutionary storage density and writing speed. However, owing to the extremely large exchange energy barriers, energy-efficient manipulation has been a fundamental challenge in AFM systems. Here, we report an electrical writing of antiferromagnetic orders through a record-low current density on the order of 10 6 A cm -2 facilitated by the unique AFM-ferromagnetic (FM) phase transition in FeRh. By introducing a transient FM state via current-induced Joule heating, the spin-orbit torque can switch the AFM order parameter by 90° with a reduced writing current density similar to ordinary FM materials. This mechanism is further verified by measuring the temperature and magnetic bias field dependences, where the X-ray magnetic linear dichroism (XMLD) results confirm the AFM switching besides the electrical transport measurement. Our findings demonstrate the exciting possibility of writing operations in AFM-based devices with a lower current density, opening a new pathway towards pure AFM memory applications., (© 2022. The Author(s).)

Synthetic antiferromagnets (SAFs), composed of Ru spacer with a Re insertion layer, reveal superior thermal stability up to 450 °C annealing, making the back-end of line process a wider manufacturing window and tolerance to integrate the perpendicular magnetic tunneling junctions (P-MTJs) into CMOS process. The coupling strength decays significantly for SAFs with single Ru spacer after annealing above 400 °C. Due to the characteristics of refractory metals, Re can behave as a diffusion barrier during annealing. Furthermore, the Re spacer can still keep reasonable RKKY coupling strength. Therefore, the SAFs with Ru/Re composite spacers exhibit higher RKKY coupling strength than Ru spacers after 450 °C annealing. In addition, we discovered the different enhancements for the upper and lower interfacial Re insertion, which was attributed to the varied defect formation at interfaces. The stacking fault was formed at the upper Ru/Co interface in as-deposited state. When Re was inserted at the upper interface, the diffusion between Co and Ru was significantly suppressed and the stacking fault can be eliminated during annealing, leading to enhanced interlayer coupling. Through the interfacial engineering, we may have more degrees of freedom to tune the SAF performance and thus enhance process compatibility of P-MTJ to the CMOS process., (© 2021. The Author(s).)

A one-step sputtering process using a quaternary target has been demonstrated to be a simple route to form Cu(In,Ga)Se 2 (CIGSe) absorber without post-selenization; however, the lack of a Ga-grading structure in the CIGSe absorber confines its efficiency. Here, we demonstrate a one-step cosputtering process to control the Ga profile in the CIGSe absorber on flexible stainless steel substrates. Special attention was paid to the formation of second phases and their effects on the cell performance. Although the normal Ga-grading and efficiency enhancement could be achieved by cosputtering of CIGSe and Ga 2 Se 3 targets, high-energy ion bombardment during the sputtering process might cause the decomposition of the Ga 2 Se 3 target, leading to the formation of Ga 2 O 3 in the CIGSe absorber, which gradually degraded the device performance. We replaced the Ga 2 Se 3 target with a stoichiometric CuGaSe 2 target for cosputtering, which can further enhance the cell efficiency due to the elimination of Ga 2 O 3 . However, when the Ga content at the back side of CIGSe is further increased by raising the deposition power of the CuGaSe 2 target, the phase separation of CuGaSe 2 may take place, resulting in the formation of Cu 2- X Se and CuGaSe 2 at the back side of the CIGSe absorber; therefore, the recombination at the back side is increased. By cosputtering a CIGSe target with a Cu-deficient CuGaSe 2 target, we can suppress the formation of second phases and achieve designable normal grading, leading to the highest efficiency of 15.63% without post-selenization on flexible substrates.

Improving power conversion efficiency of photovoltaic devices has been widely investigated; however, most research studies mainly focus on the modification of the absorber layer. Here, we present an approach to enhance the efficiency of Cu(In,Ga)(S,Se) 2 (CIGSSe) thin-film solar cells simply by tuning the CdS buffer layer. The CdS buffer layer was deposited by chemical bath deposition. Indium doping was done during the growth process by adding InCl 3 into the growing aqueous solution. We show that the solar cell efficiency is increased by proper indium doping. Based on the characteristics of the single CdS (with or without In-doping) layer and of the CIGSSe/CdS interface, we conclude that the efficiency enhancement is attributed to the interface-defect passivation of heterojunction, which significantly improves both open circuit voltage and fill factor. The results were supported by SCAPS simulations, which suggest that our approach can also be applied to other buffer systems.

The growth of large-area epitaxial transition metal dichalgogenides (TMDCs) are of central importance for scalable integrated device applications. Different methods have been developed to achieve large-sized high quality films. However, reliable approaches for centimeter-sized or even wafer-level epitaxial growth of TMDCs are still lacking. Here we demonstrate a new method to grow inch-sized epitaxial WSe 2 films on SiO 2 /Si substrates at a much lower temperature with high repeatability and scalability. High quality crystalline films are achieved through direct selenization of a tungsten film with platinum as the underlayer. The self-assembled PtSe 2 buffer layer, formed during selenization, assists epitaxial growth of WSe 2 . Using fabricated WSe 2 films, excellent performance memory devices are demonstrated. As a member of the TMDC family, our findings based on WSe 2 may also be applied to other TMDC materials for large-scale production of high quality TMDC films for various applications.

Exchange bias, a shift in the hysteresis loop of a ferromagnet arising from interfacial exchange coupling between adjacent ferromagnetic and antiferromagnetic layers, is an integral part of spintronic devices. Here, we show that spin-orbit torque generated from spin current, a promising approach to switch the ferromagnetic magnetization of next-generation magnetic random access memory, can also be used to manipulate the exchange bias. Applying current pulses to a Pt/Co/IrMn trilayer causes concurrent switching of ferromagnetic magnetization and exchange bias, but with different underlying mechanisms. This implies that the ferromagnetic magnetization and exchange bias can be manipulated independently. Our work demonstrates that spin-orbit torque in ferromagnet/antiferromagnet heterostructures facilitates independent manipulations of distinct magnetic properties, motivating innovative designs for future spintronics devices.

The considerable advances that have been made in the development of organotypic cultures have failed to overcome the challenges of expressing tissue-specific functions and complexities, especially for organs that require multitasking and complex biological processes, such as the liver. Primary liver cells are ideal biological building blocks for functional organotypic reconstruction, but are limited by their rapid loss of physiological integrity in vitro. Here the concept of lattice growth used in material science is applied to develop a tissue incubator, which provides physiological cues and controls the 3D assembly of primary cells. The cues include a biological growing template, spatial coculture, biomimetic radial flow, and circulation in a scaffold-free condition. The feasibility of recapitulating a multiscale physiological structural hierarchy, complex drug clearance, and zonal physiology from the cell to tissue level in long-term cultured liver-on-a-chip is demonstrated. These methods are promising for future applications in pharmacodynamics and personal medicine., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We propose a simple approach to engineering the sputtered In x (O,S) y /Cu(In,Ga)Se 2 heterojunction, in terms of band alignment and interface properties. The band alignment was tailored by tuning the base pressure of the sputtering deposition to incorporate oxygen into deposited In 2 S 3 layers (termed as In x (O,S) y ). The interface properties were improved by optimizing the air-annealing temperature on In x (O,S) y /Cu(In,Ga)Se 2 stacked layers. Increasing the base pressure raises the O/(S + O) ratio contained in deposited In x (O,S) y films and thus widens the band gaps. This could effectively tailor the conduction band offset (ΔE C ) at the In x (O,S) y /Cu(In,Ga)Se 2 interface from a cliff (-0.25 eV) to a nearly flat band (0.07 eV) alignment. On the other hand, the extra air annealing at 235 °C did not significantly change the band alignment but did ameliorate the interface properties by reducing the Cu content at the Cu(In,Ga)Se 2 surface and diminish the interface defect density induced by sputtering damages. The former might enhance the type of inversion and increase the hole barrier at the interface, preventing the detrimental recombination behavior. The latter could effectively strengthen the junction quality. Consequently, our approach substantially enhances the cell efficiency from 2.30% to 11.04%.

By engineering multidomain formation in Co/Pt multilayers, it is demonstrated how multilevel storage can be achieved by spin-orbit torque switching. It is rather remarkable that, by modulating the writing pulse conditions, the final magnetization states can be controlled, independent of the initial configurations. The initialization-free multilevel memory advances the spin-orbit-torque magnetic random access memory to higher storage density for practical applications., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Magnetic and multiferroic nanocomposites with two distinct phases have been a topic of intense research for their profound potential applications in the field of spintronics. In addition to growing high-quality phase separated heteroepitaxial nanocomposites, the strain engineering that is conducive to enhance the tunability of material properties, in general, and the magnetic properties, in particular, is of utmost importance in exploring new possibilities. Here, we investigated the magneto-structural coupling between antiferromagnetic BiFeO3 (BFO) and ferrimagnetic CoFe2O4 (CFO) in self-assembled vertically aligned nanocomposites grown on LaAlO3 (LAO) and SrTiO3 (STO) substrates. We found that BFO exhibits tetragonal (T) and rhombohedral (R) structures as the stable phases and CFO has high magnetocrystalline anisotropy even in the form of nanocomposites. The temperature and magnetic field dependent magnetizations of T_BFO-CFO/LAO and R_BFO-CFO/STO nanocomposites primarily demonstrate the magnetoelastic coupling between these variants.

A design for the fabrication of metallic nanoparticles is presented by thermal dewetting with a chemically heterogeneous nano-template. For the template, we fabricate a nanostructured polystyrene-b-polydimethylsiloxane (PS-b-PDMS) film on a Si|SiO2 substrate, followed by a thermal annealing and reactive ion etching (RIE) process. This gives a template composed of an ordered hexagonal array of SiOC hemispheres emerging in the polystyrene matrix. After the deposition of a FePt film on this template, we utilize the rapid thermal annealing (RTA) process, which provides in-plane stress, to achieve thermal dewetting and structural ordering of FePt simultaneously. Since the template is composed of different composition surfaces with periodically varied morphologies, it offers more tuning knobs to manipulate the nanostructures. We show that both the decrease in the area of the PS matrix and the increase in the strain energy relaxation transfer the dewetted pattern from the randomly distributed nanoparticles into a hexagonal periodic array of L10 FePt nanoparticles. Transmission electron microscopy with the in situ heating stage reveals the evolution of the dewetting process, and confirms that the positions of nanoparticles are aligned with those of the SiOC hemispheres. The nanoparticles formed by this template-dewetting show an average diameter and center-to-center distance of 19.30 ± 2.09 nm and 39.85 ± 4.80 nm, respectively. The hexagonal array of FePt nanoparticles reveals a large coercivity of 1.5 T, much larger than the nanoparticles fabricated by top-down approaches. This approach offers an efficient pathway toward self-assembled nanostructures in a wide range of material systems.

In this study, advanced control of crystallographic orientations and magnetic properties of self-assembled nanostructures via rational selections of substrates is demonstrated. We show that in the perovskite-spinel BiFeO(3)-CoFe(2)O(4) model system the crystal orientation of self-assembled CoFe(2)O(4) nanopillars can be tuned among (001), (011), and (111), while that of the BiFeO(3) matrix is fixed in (001). Moreover, the resultant CoFe(2)O(4) nanopillars appear in various shapes: pyramid, roof, and triangular platform, respectively. The tunable nanostructures through this approach enable the control of material functionality such as the magnetic anisotropy of CoFe(2)O(4). This study opens a new pathway for the engineering of self-assembled heteroepitaxial nanostructures.