The construction and control of large-scale quantum systems is one of the grand challenges in contemporary science. The ability to do so would enable us to unlock fundamentally new technological capabilities in the form of quantum simulation and computation. Once available, these technologies are widely anticipated to lead to solutions to so-far unsolvable problems across a multitude of fields such as materials science, drug discovery, or computer science. As such, quantum technology has exceptional potential to benefit society. The critical challenge for building suitable quantum devices lies in the inherent fragility of quantum states: we must find physical quantum systems that represent the logical units of a quantum machine, quantum bits or qubits, with long, intrinsic coherence times (i.e., the time that a quantum state can be kept intact) while at the same time maintaining the ability to control them. This proposal aims to find the means to effectively enhance the available coherence in one of the most promising platforms for quantum computation, superconducting qubits, by developing quantum memories based on naturally extremely coherent spins. Through the design of specifically tailored coupling circuits, this proposal will realize efficient interfaces between superconducting qubit devices and ensembles of spins and allow storage and retrieval of quantum states that are suited for quantum computation. In superconducting circuits, a leading platform for quantum computation, coherence limits are set by materials and methods to fabricate the circuits. The central research goal of this project is the experimental realization of the storage of logically encoded qubits in long-lived spin ensembles. Using state-of-the-art parametric couplers, this work aims to efficiently transfer quantum information from superconducting qubits to harmonic oscillator modes realized by the ensembles. This capability will result in the creation of logical qubit states in the form o